text:
Volume III, Issue 5 | September 25, 2017
The Power of Second Chances
Volume III, Issue 5
The VIPs Speak Out
The Broad Stage Recommits to Its SMC Relationship
Service to Country, College, and Community
Ilona Gerbakher is living proof of the power of second chances. At 15, she was a straight F student.
"I don't think I went to class once in my freshman year," she said.
Today, she's a PhD candidate in Islamic studies at Columbia University, with a bright future as a scholar of the Graeco-Arab translation movement and Jewish history in the medieval Middle East.
Her inspirational story illustrates, among other things, why community college is an indispensable institution.
From Odessa to Sherman Oaks
Ilona was born in Odessa, Ukraine, in the twilight of the collapsing Soviet Union. Three generations of her Jewish family emigrated to the United States in 1989 when she was only two.
"It was the typical immigrant, two-suitcase story," she said, with a musical laugh that makes light of past hardships.
The Gerbakhers were intellectuals and professionals, but the American dream eluded them. Ilona's grandfather had been a concert pianist in Odessa. In Los Angeles, he put his musician's hands to work as a chiropractor. Her father had been an oral surgeon in his homeland, but in California he struggled to reestablish his credentials. It took him eight long years to pass his medical boards.
"We were reduced to absolute pennilessness," Ilona recalled, of her early childhood living in the Fairfax district and later in Sherman Oaks. "My father worked as a cook at a mental institution. My mother worked nights as a cleaning lady at Cantor's Deli. They did whatever they had to do. I don't remember my mom ever not working 20 hours a day. It took a heavy toll on our family."
In Ilona's first week as a high school freshman, against the backdrop of 9/11, her parents divorced. Almost overnight, she went from honors student to full-time truant.
"I just couldn't handle school," she said. "I struggled to recover from my family breaking apart. My father left. My mother was working as a dental assistant, and she wasn't home much. My grandmother and grandfather were working full time. It was very dislocating."
By junior and senior years, Ilona was back on track, earning A's in her all-AP schedule of classes and making a name for herself on the debate squad, even winning a state champion title in impromptu.
"But it was too late," Ilona said. "I graduated Taft with a 2.7 GPA, in the bottom third of my class." Her teachers had made up their minds about her. Informed by the school admissions advisor that she was "not college material," Ilona went home and cried.
Luckily no one at Santa Monica College agreed with that assessment.
Falling in Love with Arabic
Ilona thrived at SMC, majoring in philosophy and excelling at debate. She earned first-place trophies for the Corsairs in extemporaneous and impromptu speech at the 2008 nationals, and she co-captained the team in 2009. "I'm very extraverted, and I love talking," she said, explaining her debating success.
Later that fall, she transferred to UCLA, continuing to coach the Corsairs in her spare time. By then, though, she had found her life's calling: as an Arabist.
Ilona had always been good with languages. Russian, French, and biblical Hebrew were woven into her early childhood education, and Slavic languages—Polish, Ukrainian, and Belarusian—came naturally. In 2009, during a summer internship as a translator at the U.S. Holocaust Memorial Museum in Washington, D.C., she decided to try her golden tongue on something new. A visiting Persian-Israeli scholar needed help cleaning up her English translations, and Ilona traded her manuscript-editing services for Arabic lessons. She fell in love with it almost instantly.
At UCLA, she threw herself into Arabic, changing her philosophy major to Middle Eastern and North African studies. Over the next two years, she won many honors and academic prizes, finishing magna cum laude in 2011. From there, she landed a presidential scholarship to Harvard Divinity School, where she completed her masters degree in Islamic theology in 2013.
Teaching and research fellowships have taken her all over the Arabic-speaking world, including Morocco, Qatar, and Israel. In addition to classical and modern standard Arabic, Ilona has since mastered the Moroccan and Palestinian dialects. She's also proficient in Farsi, Pahlavi (medieval Persian), ancient Greek (both Attic and Koine) and Aramaic.
Currently she's pursuing her PhD in Islamic studies at Columbia University. Three years into her program, she's just rolling up her sleeves to begin her dissertation. Her proposed topic: the courtesans of 9th century Baghdad.
She has two other writing projects in the hopper: a textbook chapter on the Qalandar Sufi sect of central Asia, and another on the political language of Islam. Both are in collaboration with her graduate advisor, Columbia religion professor Katherine Ewing.
This fall, she's heading back to the Middle East on an advanced Arabic language fellowship through Harvard's Center for Arabic Study Abroad.
Like Fuel in a Rocket
After her PhD, Ilona plans to go on the academic job market. With UCLA, Harvard and Columbia on her resume, she'll likely do well. But looking back, she attributes much of her success not to these elite institutions.
"Like fuel in a rocket, a lot of what I am today, it happened at SMC," she said. "I never had a professor question my capacity. I never had anyone make me feel stupid or less-than. They all said, 'Of course, you're smart. Of course, you're going to do great things.' And that—to a young person, especially when they've struggled—is really redemptive."
Asked where she'd like to end up teaching, Ilona doesn't hesitate.
"I want to be back here in LA, and I want to teach either at SMC or UCLA," she said. "I love both my almae matres. These are schools that serve low- and middle-income students the most. I think it's really important to help give students the opportunities that I was given by the teachers at SMC and UCLA. It's very hard to be an immigrant. And it's very hard to be a transfer student. I understand that. As a professor, I want to also be a mentor."


rrently DJs at various Lindy Hop and Blues Dancing in San Francisco including Fr iday Night Blues, 9:20 Special, Swing Central, and Savannah Jazz. Roy has also D Jed at local venues when he lived in Chicago(2000-2005) and Tampa(1999-2000). Ro	.. (expand) y has DJed at many national exchanges and events in cities including; Chicago, C leveland, New Orleans, San Francisco, Moscow, South Florida, Tampa, Los Angeles, St. Louis, Minnesota, and New York.


text:
Research ArticleSPINTRONICS
Anomalous spin-orbit torque switching due to field-like torque–assisted domain wall reflection
Jungbum Yoon1,*,†,
View ORCID ProfileSeo-Won Lee2,*,
Jae Hyun Kwon1,
Jong Min Lee1,
Jaesung Son1,
Xuepeng Qiu3,
View ORCID ProfileKyung-Jin Lee2,4,‡ and
Hyunsoo Yang1,‡
1Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore.
2Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea.
3Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China.
4KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Republic of Korea.
↵‡Corresponding author. Email: eleyang{at}nus.edu.sg (H.Y.); kj_lee{at}korea.ac.kr (K.-J. L.)
↵† Present address: Center for Nanometrology, Korea Research Institute of Standards and Science, Daejeon 34113, Republic of Korea
Science Advances 21 Apr 2017:
Jungbum Yoon
Seo-Won Lee
ORCID record for Seo-Won Lee
Jae Hyun Kwon
Jong Min Lee
Jaesung Son
Xuepeng Qiu
Kyung-Jin Lee
ORCID record for Kyung-Jin Lee
For correspondence: eleyang@nus.edu.sg kj_lee@korea.ac.kr
Hyunsoo Yang
Spin-orbit torques (SOTs) allow the electrical control of magnetic states. Current-induced SOT switching of the perpendicular magnetization is of particular technological importance. The SOT consists of damping-like and field-like torques, and understanding the combined effects of these two torque components is required for efficient SOT switching. Previous quasi-static measurements have reported an increased switching probability with the width of current pulses, as predicted considering the damping-like torque alone. We report a decreased switching probability at longer pulse widths, based on time-resolved measurements. Micromagnetic analysis reveals that this anomalous SOT switching results from domain wall reflections at sample edges. The domain wall reflection was found to strongly depend on the field-like torque and its relative sign to the damping-like torque. Our result demonstrates a key role of the field-like torque in deterministic SOT switching and the importance of the sign correlation of the two torque components, which may shed light on the SOT switching mechanism.
Spintronics
spin-orbit torque
magnetization switching
magneto optical Kerr effect
domain wall
Spin-orbit coupling can convert charge currents to spin currents (1–8). The ability to generate spin currents without the help of ferromagnets constitutes a core building block of an emerging research field, spin orbitronics, which uses spin-orbit coupling as a spin-current source in spintronic devices. When the spin current from spin-orbit coupling is absorbed by a ferromagnet, it exerts a spin-orbit torque (SOT) on the ferromagnet. The SOT can switch magnetization (9, 10) and induce fast domain wall motion (11–13) in ferromagnet/heavy metal bilayers. The SOT switching of the perpendicular magnetization is of particular technological relevance because perpendicular magnetic random access memories have a better scalability than in-plane ones.
From the viewpoint of fundamental physics and its applications, it is of critical importance to understand the detailed SOT characteristics and consequent magnetization dynamics. The microscopic origin of SOT remains under debate (9, 10, 14–26), but it is commonly decomposed into two mutually orthogonal vector components, the damping-like torque (DLT) and field-like torque (FLT). SOT-induced magnetization dynamics, including the DLT and FLT terms, is described by the Landau-Lifshitz-Gilbert equation
(1)where γ is the gyromagnetic ratio,
is the unit vector along the magnetization, μ0Heff is the effective magnetic field, including the external, anisotropic, magnetostatic, and exchange fields, and α is the damping constant. τd (
) and τf (
) describe the magnitudes of DLT and FLT, respectively (in magnetic field units), where J is the current density, Ms is the saturation magnetization, d is the thickness of ferromagnet, c|| and c⊥ are the DLT and FLT efficiencies, respectively, and ŷ is the unit vector perpendicular to both the current direction and the inversion asymmetry direction (that is, thickness direction; see coordinate system in Fig. 1A). From Eq. 1, we found that the two torque components affect magnetization dynamics in distinctly different ways: The DLT directs the magnetization toward the y axis, whereas the FLT induces magnetization precessions around the y axis.
Fig. 1 TR-MOKE experimental setup and dc-induced magnetization switching in Ta/CoFeB/MgO.
(A) Schematic illustration of TR-MOKE measurements. μ0Hx is the external magnetic field. The dc or pulse current is applied along the x axis. The picosecond laser is shined as a probe beam. The patterned perpendicular anisotropy Ta (6 nm)/CoFeB (0.8 nm)/MgO (2 nm) square is connected to a ground (G)–signal (S)–ground (G) coplanar waveguide. (B) dc-induced magnetization switching with various μ0Hx. The data are shifted vertically for clarity. (C) dc switching current density Jc versus μ0Hx.
Most of the previous SOT-switching studies have considered DLT as a main driving source but ignored the FLT. When considering DLT alone, the switching trajectory in the macrospin approximation is expected to be simple without magnetization precessions (27). This DLT-dominated switching leads to an increased switching probability with the current pulse width, consistent with previous quasi-static measurements (28, 29) and also in accordance with common belief. However, in some ferromagnet/heavy metal bilayers (for example, Ta-based bilayers), the FLT is significant (30–32). For a sizable FLT, it has been theoretically predicted that the magnetization precession induced by the FLT complicates magnetization dynamics, especially for the case wherein the sign of FLT is the opposite to that of DLT (in our sign convention; see Eq. 1) (33–35). In this respect, it is important to experimentally investigate the role of FLT in the SOT switching. Note that previous quasi-static measurements based on Hall bar detection (9, 10, 28, 29) or magneto-optical Kerr effect (MOKE) microscopy (36) would be unable to capture the core effect of FLT because this may induce fast dynamics (that is, magnetization precessions around the y axis). To overcome this limitation, it is essential to perform time-resolved (TR) measurements (37, 38), which provide an important step toward a better understanding of SOT-induced magnetization dynamics.
Here, we report SOT-induced magnetization dynamics in time domain by TR-MOKE measurements for Ta/CoFeB/MgO heterostructures with perpendicular magnetic anisotropy. This Ta-based structure has a large FLT (that is, |τf /τd| ≈ 4) whose sign is the opposite to that of DLT (32), such that it allows a detailed study of the FLT effect on SOT switching. The temporal evolution of the magnetization is detected by the stroboscopic pump-probe technique with an electrical pulse generator (pump) and a picosecond laser (probe) (see section S1), as shown schematically in Fig. 1A. We observe an anomalous SOT-induced switching behavior, in which the switching probability increases at short current pulses but decreases at longer pulses. On the basis of micromagnetic simulations, we interpret this anomalous switching behavior as a consequence of FLT-assisted domain wall reflection at sample edges.
TR measurements of perpendicular magnetization switching by SOT
We first perform a static polar MOKE measurement using an in-plane dc I with an external in-plane magnetic field μ0Hx along the x axis to examine the dc SOT switching characteristics of the Ta (6 nm)/CoFeB (0.8 nm)/MgO (2 nm) sample (device 1). The pattern size of device 1 is 3 μm × 3 μm, which is large enough to detect SOT-induced change in the MOKE signal. Figure 1B shows MOKE signals as a function of dc with various in-plane magnetic fields. As a polar MOKE signal probes the average z component of CoFeB magnetization (〈Mz〉) in a laser spot, where a high (low) signal corresponds to the 〈Mz〉-up (〈Mz〉-down) magnetic state, the hysteretic curves show SOT-induced deterministic magnetization switching. The switching polarity is determined by the direction of the current and Hx (9, 10): The up-to-down switching occurs in a positive (negative) current with a negative (positive) Hx. As shown in Fig. 1C, the dc switching current density Jc decreases with increasing Hx, in agreement with previous reports using Hall bar experiments (9, 20).
We next carry out TR measurements by injecting a current pulse with various pulse widths (that is, tpw ≤ 5 ns, J = 5.2 × 1011 A m−2, and μ0Hx = −168 mT) and by detecting the magnetic state in time domain through TR-MOKE signal (Fig. 2A). The current pulse is turned on at t = 0 (that is, current-on) and turned off at a time indicated by a red triangle in each curve (that is, current-off). The horizontal dashed lines serve as guides for the maximum change in MOKE signal (~7 μV), corresponding to full magnetization switching from the up to the down state.
Fig. 2 TR-MOKE measurements of SOT-induced perpendicular magnetization switching in Ta/CoFeB/MgO.
(A) Temporal evolutions of TR-MOKE signals corresponding to the average z component of magnetization (Mz) in an applied current density (J = 5.2 × 1011 A m−2) of various pulse widths (tpw) from 1 to 5 ns for μ0Hx = −168 mT. The data are shifted vertically for clarity. The current pulse starts at t = 0, and the end of the current pulse is indicated as a red triangle in each curve. The horizontal dashed lines serve as guides to the maximum change in MOKE signal (~7 μV), corresponding to the full magnetization switching from the up to the down state. (B) Time-varying MOKE signal for tpw = 1.8 and 5.0 ns. (C) Switching probability (Psw) as a function of tpw, extracted from Fig. 2A.
For short pulses (tpw ≤ 1.6 ns), the MOKE signal change is smaller than 7 μV, indicating that the current pulse is too short to switch the magnetization. For an increase of tpw to 1.8 ns, a complete switching is achieved, as evidenced by a signal change of ~7 μV (by defining the final magnetic state at t = 8 ns). However, when tpw > 2.5 ns, we observe an anomalous temporal change in the TR-MOKE signal: It decreases in the initial time stage (<2 ns) but increases back even before the current pulse is turned off.
To clarify the anomalous SOT switching behavior, we compare two cases, tpw = 1.8 and 5.0 ns, in Fig. 2B. For tpw = 1.8 ns, which corresponds to normal switching, the TR-MOKE signal decreases monotonously when the current is on, indicating that 〈Mz〉 changes monotonously from the up to the down state by SOT. This decreased signal is maintained even after the current is turned off so that the up-to-down switching is completed. On the other hand, for tpw = 5.0 ns, which corresponds to anomalous switching, the signal decreases until t = 2 ns is reached and then increases back. Note that this anomalous increase in the signal is present even before the current is off. It implies that the SOT is responsible not only for the initial decrease in the MOKE signal (that is, switching) but also for the anomalous increase in the signal (that is, switching back). The anomalous switching back phenomena are observed for all cases with tpw > 2.0 ns, as summarized in Fig. 2C, which shows the switching probability (PSW) as a function of tpw, where PSW (%) = [1 – VMOKE (t = 8 ns)/7 μV] × 100.
We next show that the anomalous switching back phenomena become more pronounced as the current amplitude increases. We perform TR-MOKE measurements at various current densities and pulse widths for a structure of Ta (3 nm)/CoFeB (1.2 nm)/MgO (2 nm) with a pattern size of 3 μm × 6 μm (device 2). As an example, Fig. 3A shows TR-MOKE signals normalized by the maximum signal change as a function of time at various current densities for tpw = 30 ns. Focusing on the normalized MOKE signal at t = 45 ns (that is, after the current is turned off), we find that a higher current density causes more switching back. Figure 3B summarizes PSW versus tpw at various current densities. It shows that the switching back phenomena become more noticeable at higher current densities.
Fig. 3 Current-dependence of SOT-induced magnetization switching.
The sample structure is Ta (3 nm)/CoFeB (1.2 nm)/MgO (2 nm)/SiO2 (3 nm). (A) Temporal evolutions of TR-MOKE signals, normalized by the maximum signal change, for various current densities for tpw = 30 ns and μ0Hx = −90 mT. (B) Switching probability (PSW) as a function of tpw at various current densities.
Anomalous SOT switching due to domain wall reflections at edges: Micromagnetic analysis
To understand the anomalous switching back phenomena, we perform micromagnetic simulations at 0 K (Fig. 4; see Materials and Methods). We use parameters of magnetic properties and SOTs [DLT (c|| = −0.07) and FLT (c⊥ = +0.28)], deduced from magnetometer (see section S2) and harmonic Hall measurements for Ta/CoFeB/MgO samples (32). Figure 4A shows temporal evolutions of normalized 〈mz〉 at various current pulse widths for J = 15 × 1011 A m−2 and μ0Hx = −200 mT. The current-off time is depicted as a vertical dashed line for each case. For tpw = 1.5 and 1.6 ns, the current pulse is too short to switch the magnetization, whereas for tpw = 1.7 ns, a full switching is achieved. The switching back is observed for a longer pulse (tpw = 1.8 ns): 〈mz〉 returns back to the initial state (〈mz〉 = +1) after the current is turned off. Figure 4B shows a switching parameter P as a function of tpw, where P is defined as "1" ("0") for the switching (no-switching) event. We find that the switching back (equivalently no-switching event) is not unique for the case of tpw = 1.8 ns but appears in a somewhat oscillatory manner for tpw > 1.8 ns. Note that the oscillation is not periodic. This nonperiodic oscillatory switching obtained from the zero-temperature calculation (Fig. 4B) can explain the decreased switching probability at longer pulses observed in the room temperature measurement (Fig. 2C) because the thermal effect randomizes the oscillatory switching dynamics. In section S3, we show micromagnetic simulation results for detailed oscillatory switching dynamics.
Fig. 4 Micromagnetic simulation results for SOT switching at 0 K.
(A) Temporal evolutions of average Mz/Ms (〈mz〉) at various current pulse widths. (B) Switching parameter (P; 0 = no-switching and 1 = switching) as a function of tpw for J = 15 × 1011 A m−2 and μ0Hx = −200 mT. (C) Temporal evolutions of 〈mz〉 at various current densities for tpw = 1.2 ns and μ0Hx = −200 mT. Snapshots of magnetization configuration (mz = Mz/Ms) at time t for tpw = 1.7 ns (D) and 1.8 ns (E). Yellow arrows show the direction of domain wall motion. (F) Switching parameter P as a function of tpw for various current densities (J = 16 × 1011, 18 × 1011, and 20 × 1011 A m−2).
Micromagnetic simulations reveal that the switching back phenomena originate from the domain wall reflection at sample edges in the presence of current (thus SOT), as discussed below. We show temporal evolutions of mz for tpw = 1.7 and 1.8 ns, corresponding to the switching (Fig. 4D) and switching back (Fig. 4E), respectively. For both cases, in the initial time stage (t < 1.7 ns), a reversed domain is nucleated at a corner and then expands isotropically. For tpw = 1.7 ns, the current is turned off at the moment when the domain wall arrives at sample edges. In this case, the domain wall remains moving in the same direction as before because of inertia (39–41), even after the current is turned off. As a result, a full switching is achieved. On the other hand, for tpw = 1.8 ns, the current is still turned on when the domain wall arrives at sample edges. In this case, the domain wall is reflected from the edges and moves in the opposite direction, leading to switching back. Therefore, the domain wall reflection at sample edges in the presence of SOT is key to explaining the anomalous switching back phenomena.
The domain wall reflection at sample edges also explains the current-dependent switching back behavior shown in Fig. 3. Figure 4C shows temporal evolutions of 〈mz〉 at various current densities when tpw = 1.2 ns and μ0Hx = −200 mT. At a low current density, a reversed domain is not nucleated (J = 14 × 1011 A m−2), or the domain wall is unable to reach the sample edges (J = 16 × 1011 A m−2). At an increased current density (J = 18 × 1011 A m−2), a full switching occurs. However, at a higher current density (J = 20 × 1011 A m−2), 〈mz〉 initially decreases but returns to the initial state because of the domain wall reflection (see section S3). Figure 4F shows the switching parameter P as a function of tpw at various current densities. Similar to the results shown in Fig. 4B, the switching back appears in a somewhat oscillatory manner. The no-switching event (P = 0) becomes more frequent for a higher current density when tpw exceeds a threshold to enable the switching. This behavior is consistent with experimental observations (Fig. 3), in which the switching back phenomena become more pronounced as the current amplitude increases.
Effect of FLT on the domain wall reflection: Collective coordinate analysis
To understand the effect of FLT on the domain wall reflection, we investigate domain wall dynamics based on a semi–one-dimensional micromagnetic model. We first show the domain wall moving along the bottom edge in a two-dimensional sample (Fig. 4, D and E), where a Néel-type domain wall is stabilized by Hx at this edge. Figure 5A shows temporal evolutions of the domain wall position at various FLT to DLT ratios (that is, τf/τd = c⊥/c||) for J = 6 × 1011 A m−2 and μ0Hx = −200 mT. Here, we fix the DLT efficiency c|| as −0.07 and vary the FLT efficiency c⊥. For all cases, the domain wall is reflected at the edge (located at 2 μm), exhibits a backward motion for a while, and then moves back to the edge again. After several reflections, the domain wall eventually annihilates at the edge, and the switching is completed. This domain wall reflection is understood by the reflection of a transverse wave at a fixed end. It is known that the phase of a transverse wave changes by π when the wave is reflected at a fixed end (Fig. 5B). Because a domain wall can be decomposed into transverse spin waves, the phase change corresponds to a change in the domain wall angle φ upon reflection (see Fig. 5C for schematics). The most important feature in Fig. 5A is that the distance Δq (defined as a positive value) for the backward domain wall motion strongly depends on the magnitude and sign of τf/τd. For a positive τf/τd, Δq is small and the domain wall annihilates soon after it reaches the sample edge. On the other hand, for a negative τf/τd, Δq is large, which in turn causes a noticeable switching back behavior, as shown in Fig. 4E. For a domain wall moving along the left edge (parallel to the y axis), where the Bloch-type domain wall is stabilized by Hx, it experiences a similar reflection process due to the same symmetry of domain wall angle and SOT (see section S4).
Fig. 5 Domain wall reflection in one-dimensional model.
(A) Temporal evolutions of the domain wall position q at various FLT to DLT ratios (τf/τd = c⊥/c||) for c|| = −0.07, J = 6 × 1011 A m−2, and μ0Hx = −200 mT. Δq is the distance for the backward motion of a reflected domain wall. Schematic illustrations of the reflection of a transverse wall at a fixed end (B), and the reflection of a domain wall at an edge (C). (D) Temporal evolutions of domain wall angle φ and domain wall position q for τf/τd = −2. Domain wall angles φstd, φM, φref, and φ0 are defined in (C) and (D) (see the text for details). (E) φref, φ0, and φstd as a function of τf/τd. (F) Δq as a function of τf/τd.
We adopt the collective coordinate approach for the domain wall position q and domain wall angle φ (see section S5) (42–46) to explain the dependence of Δq on the magnitude and sign of τf/τd. We define three domain wall angles, φref, φ0, and φstd (see Fig. 5, C and D): φref is the angle just after the reflection, φ0 is the angle at which the backward domain wall motion reverses to the forward motion, and φstd is the angle for the steady-state motion before the reflection. Note that φref = 2φM − φstd, where φM(≡π − tan−1(τf/Hx)) describes the domain tilting in the film plane (see Fig. 5C). Because the edge acts as a fixed end, the domain wall component transverse to the azimuthal angle φM of the magnetization is reversed upon reflection. That is, φstd, the angle of incoming domain wall, can be rewritten as φstd = φM + (φstd − φM), where the first (second) term is longitudinal (transverse) to the domain angle φM. Upon reflection, only a transverse component is reversed (that is, changes its sign), whereas a longitudinal component is conserved. Therefore, φref = φM − (φstd − φM) = 2φM − φstd.
From the collective coordinate approach, we obtain for −Hx > τf > 0 (see section S5)
(4)where
, and HK,eff is the effective anisotropy field. We find that Eqs. 2 to 4 describe general tendencies of the numerically obtained three domain wall angles with respect to τf/τd (Fig. 5E). Some disagreement for φref can be attributed to the dynamically distorted domain wall profile just after the reflection.
From the collective coordinate approach, assuming a small damping, an approximate Δq is given as (see section S5 for details)
(5)where λ is the domain wall width. Figure 5F shows that Eq. 5 qualitatively describes the numerical results of the dependence of Δq on τf/τd. Note that the first term of Eq. 5 dominates over the second term (Fig. 5F). Therefore, the dependence of Δq on τf/τd is mostly governed by cos φ0/cos φref. Also note that φref changes more rapidly with τf/τd than φ0 (Fig. 5E). Therefore, the FLT dependence of φref is key to understanding a large backward domain wall motion for a negative τf/τd. From Eq. 3, the FLT-dependence of φref is described by −2 tan−1(τf/Hx) (thus, φM) in a small damping approximation, which means that the FLT affects the backward domain wall motion through its effect on φM.
We demonstrate that the FLT has a crucial role in the SOT switching and causes the anomalous switching back phenomena when it is large and its sign is the opposite to that of DLT. Our result suggests that not only DLT but also FLT should be carefully examined to achieve deterministic SOT switching. Furthermore, our result raises a question on the microscopic origin of SOT: What determines the sign correlation between DLT and FLT? To our knowledge, the sign product of DLT and FLT in all previous experiments has been negative (in our sign convention) except for a data point by Kim et al. (30), of which the spin-orbit effective field is too small to unambiguously determine the sign product. For instance, in our previous work (26), the signs of DLT and FLT vary with the oxidation of a ferromagnet, but the sign product is always negative. If this fixed sign product is true, it indicates that a single dominant mechanism is responsible for both DLT and FLT. It is in contrast to the currently widely accepted argument that the DLT (FLT) originates from the bulk spin Hall effect in a heavy metal layer (the Rashba effect at the ferromagnet/heavy metal interface). Notably, in theories for the bulk spin Hall mechanism, the sign product is positive (20) for a positive imaginary part of the spin-mixing conductance (47). On the other hand, in theories for the Rashba mechanism, the sign product is negative (17, 25).
We have demonstrated the anomalous switching back phenomena in rather large samples (a few square micrometers), which is required to obtain detectable MOKE signals. However, note that these results could be applicable to nanosized samples (a few tens of nanometers), as long as the sample size is larger than the domain wall width because the domain wall dynamics is key to the anomalous switching back phenomena.
Sample fabrication and TR-MOKE measurements
The magnetic films of Ta (6 nm)/Co40Fe40B20 (0.8 nm)/MgO (2 nm)/SiO2 (3 nm) and Ta (3 nm)/Co40Fe40B20 (1.2 nm)/MgO (2 nm)/SiO2 (3 nm) were deposited on the thermally oxidized silicon substrates by magnetron sputtering with a base pressure of <2 × 10−9 torr at room temperature and patterned into a square of 3 μm × 3 μm or 3 μm × 6 μm. For a short pulse excitation, the ground-signal-ground (GSG) coplanar waveguide was patterned with electron-beam lithography and deposited with Ta (3 nm)/Cu (75 nm)/Ta (4.5 nm). In the stroboscopic pump-probe experiments, the pulse generator (pump) and the picosecond laser (probe) controller were synchronized by the pattern generator with a triggering frequency of 100 kHz, and each data point of TR-MOKE signal corresponded to an average of 60,000 events. The spot diameter of the laser beam was 2 μm. The reflected laser beam was measured by a balanced photodetector to obtain the MOKE signal. Measurements were carried out on three devices and showed similar results.
Micromagnetic simulations
Micromagnetic simulations were carried out by numerically solving Eq. 1 at zero temperature. The following parameters were used: Ms = 1.0 × 106 A m−1, exchange stiffness constant Aex = 1.0 × 10−11 J m−1, perpendicular anisotropy constant K⊥ = 0.9 × 106 J m−3, α = 0.02, c|| = −0.07, and c⊥ = +0.28. The sample dimension for Fig. 4 was 200 nm × 200 nm × 1 nm, and the unit cell size was 2 nm × 2 nm × 1 nm. The sample dimension for Fig. 5 was 2000 nm × 50 nm × 1 nm, and the unit cell size was 2 × 50 × 1 nm3. For the current pulse, both rise and fall times were 100 ps. In our sign convention, a negative DLT efficiency (c|| < 0) induced an up-to-down switching for J > 0 and Hx < 0. For two-dimensional micromagnetic simulations (Fig. 4), we introduced an artificial defect at the bottom-left corner and considered local demagnetization fields to mimic a domain wall nucleation at room temperature.
Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/4/e1603099/DC1
section S1. Stroboscopic pump-probe MOKE experiments using a picosecond laser
section S2. Characterization of magnetic films
section S3. Oscillatory SOT-induced magnetization switching: Micromagnetic simulations
section S4. Domain wall moving along the left edge
section S5. Backward motion of a domain wall reflected at an edge
fig. S1. Stroboscopic pump-probe MOKE setup.
fig. S2. Vibrating sample magnetometry and MOKE measurements.
fig. S3. Time-varying z component of the magnetization and its configurations.
fig. S4. Domain wall types formed in the two-dimensional sample.
fig. S5. Temporal evolutions of domain wall position q for the Bloch-type domain wall.
This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.
M. I. Dyakonov,
V. I. Perel
, Current-induced spin orientation of electrons in semiconductors. Phys. Lett. A. 35, 459–460 (1971).
J. E. Hirsch
, Spin Hall effect. Phys. Rev. Lett. 83, 1834–1837 (1999).
S. Zhang
, Spin Hall effect in the presence of spin diffusion. Phys. Rev. Lett. 85, 393–396 (2000).
S. Murakami,
N. Nagaosa,
S.-C. Zhang
, Dissipationless quantum spin current at room temperature. Science 301, 1348–1351 (2003).
J. Sinova,
D. Culcer,
Q. Niu,
N. A. Sinitsyn,
T. Jungwirth,
A. H. MacDonald
, Universal intrinsic spin Hall effect. Phys. Rev. Lett. 92, 126603 (2004).
Y. K. Kato,
R. C. Myers,
A. C. Gossard,
D. D. Awschalom
, Observation of the spin Hall effect in semiconductors. Science 306, 1910–1913 (2004).
J. Wunderlich,
B. Kaestner,
T. Jungwirth
, Experimental observation of the spin-Hall effect in a two-dimensional spin-orbit coupled semiconductor system. Phys. Rev. Lett. 94, 047204 (2005).
S. O. Valenzuela,
M. Tinkham
, Direct electronic measurement of the spin Hall effect. Nature 442, 176–179 (2006).
I. M. Miron,
K. Garello,
G. Gaudin,
P.-J. Zermatten,
M. V. Costache,
S. Auffret,
S. Bandiera,
B. Rodmacq,
A. Schuhl,
P. Gambadella
, Perpendicular switching of a single ferromagnetic layer induced by in-plane current injection. Nature 476, 189–193 (2011).
L. Liu,
C.-F. Pai,
Y. Li,
H. W. Tseng,
D. C. Ralph,
R. A. Buhrman
, Spin-torque switching with the giant spin Hall effect of tantalum. Science 336, 555–558 (2012).
A. Thiaville,
S. Rohart,
É. Jué,
V. Cros,
A. Fert
, Dynamics of Dzyaloshinskii domain walls in ultrathin magnetic films. Europhys. Lett. 100, 57002 (2012).
S. Emori,
U. Bauer,
S.-M. Ahn,
E. Martinez,
G. S. D. Beach
, Current-driven dynamics of chiral ferromagnetic domain walls. Nat. Mater. 12, 611–616 (2013).
K.-S. Ryu,
L. Thomas,
S.-H. Yang,
S. Parkin
, Chiral spin torque at magnetic domain walls. Nat. Nanotechnol. 8, 527–533 (2013).
K. Obata,
G. Tatara
, Current-induced domain wall motion in Rashba spin-orbit system. Phys. Rev. B 77, 214429 (2008).
A. Manchon,
, Theory of nonequilibrium intrinsic spin torque in a single nanomagnet. Phys. Rev. B 78, 212405 (2008).
X. Wang,
A. Manchon
, Diffusive spin dynamics in ferromagnetic thin films with a Rashba interaction. Phys. Rev. Lett. 108, 117201 (2012).
K.-W. Kim,
S.-M. Seo,
J. Ryu,
K.-J. Lee,
H.-W. Lee
, Magnetization dynamics induced by in-plane currents in ultrathin magnetic nanostructures with Rashba spin-orbit coupling. Phys. Rev. B 85, 180404 (2012).
D. A. Pesin,
, Quantum kinetic theory of current-induced torques in Rashba ferromagnets. Phys. Rev. B 86, 014416 (2012).
E. van der Bijl,
R. A. Duine
, Current-induced torques in textured Rashba ferromagnets. Phys. Rev. B 86, 094406 (2012).
O. J. Lee,
T. J. Gudmundsen,
, Current-induced switching of perpendicularly magnetized magnetic layers using spin torque from the spin Hall effect. Phys. Rev. Lett. 109, 096602 (2012).
M. Jamali,
K. Narayanapillai,
X. Qiu,
L. M. Loong,
H. Yang
, Spin-orbit torques in Co/Pd multilayer nanowires. Phys. Rev. Lett. 111, 246602 (2013).
P. M. Haney,
H.-W. Lee,
M. D. Stiles
, Current induced torques and interfacial spin-orbit coupling: Semiclassical modeling. Phys. Rev. B 87, 174411 (2013).
, Current induced torques and interfacial spin-orbit coupling. Phys. Rev. B 88, 214417 (2013).
X. Fan,
H. Celik,
J. Wu,
C. Ni,
V. O. Lorenz,
J. Q. Xiao
, Quantifying interface and bulk contributions to spin–orbit torque in magnetic bilayers. Nat. Commun. 5, 3042 (2014).
H. Kurebayashi,
D. Fang,
A. C. Irvine,
T. D. Skinner,
V. Novák,
R. P. Campion,
B. L. Gallagher,
E. K. Vehstedt,
L. P. Zârbo,
K. Výborný,
A. J. Ferguson,
, An antidamping spin–orbit torque originating from the Berry curvature. Nat. Nanotechnol. 9, 211–217 (2014).
Y. Wu,
P. Deorani,
D.-H. Yang,
W.-S. Noh,
J.-H. Park,
, Spin–orbit-torque engineering via oxygen manipulation. Nat. Nanotechnol. 10, 333–338 (2015).
K.-S. Lee,
S.-W. Lee,
B.-C. Min,
K.-J. Lee
, Threshold current for switching of a perpendicular magnetic layer induced by spin Hall effect. Appl. Phys. Lett. 102, 112410 (2013).
C. O. Avci,
M. Baumgartner,
A. Ghosh,
O. Boulle,
P. Gambardella
, Ultrafast magnetization switching by spin-orbit torques. Appl. Phys. Lett. 105, 212402 (2014).
C. Zhang,
S. Fukami,
H. Sato,
F. Matsukura,
H. Ohno
, Spin-orbit torque induced magnetization switching in nano-scale Ta/CoFeB/MgO. Appl. Phys. Lett. 107, 012401 (2015).
J. Kim,
J. Sinha,
M. Hayashi,
M. Yamanouchi,
T. Suzuki,
S. Mitani,
, Layer thickness dependence of the current-induced effective field vector in Ta|CoFeB|MgO. Nat. Mater. 12, 240–245 (2013).
Y. Chen,
M. J. Jerry,
H. Zhang,
, Observation of the nonlocal spin-orbital effective field. Nat. Commun. 4, 1799 (2013).
, Angular and temperature dependence of current induced spin-orbit effective fields in Ta/CoFeB/MgO nanowires. Sci. Rep. 4, 4491 (2014).
G. E. Rowlands,
, Macrospin modeling of sub-ns pulse switching of perpendicularly magnetized free layer via spin-orbit torques for cryogenic memory applications. Appl. Phys. Lett. 105, 102404 (2014).
W. Legrand,
R. Ramaswamy,
R. Mishra,
, Coherent subnanosecond switching of perpendicular magnetization by the fieldlike spin-orbit torque without an external magnetic field. Phys. Rev. Appl. 3, 064012 (2015).
T. Taniguchi,
M. Hayashi
, Critical current destabilizing perpendicular magnetization by the spin Hall effect. Phys. Rev. B 92, 024428 (2015).
C. K. Safeer,
E. Jué,
A. Lopez,
L. Buda-Prejbeanu,
S. Pizzini,
G. Gaudin
, Spin–orbit torque magnetization switching controlled by geometry. Nat. Nanotechnol. 11, 143–146 (2016).
I. N. Krivorotov,
N. C. Emley,
J. C. Sankey,
S. I. Kiselev,
, Time-domain measurements of nanomagnet dynamics driven by spin-transfer torques. Science 307, 228–231 (2005).
T. Devolder,
J. Hayakawa,
K. Ito,
H. Takahashi,
S. Ikeda,
P. Crozat,
N. Zerounian,
J.-V. Kim,
C. Chappert,
, Single-shot time-resolved measurements of nanosecond-scale spin-transfer induced switching: Stochastic versus deterministic aspects. Phys. Rev. Lett. 100, 057206 (2008).
A. P. Malozemoff, J. C. Slonczewski, Magnetic Domain Walls in Bubble Materials (Academic Press, 1979).
E. Saitoh,
H. Miyajima,
T. Yamaoka,
, Current-induced resonance and mass determination of a single magnetic domain wall. Nature 432, 203–206 (2004).
R. Moriya,
C. Rettner,
S. S. P. Parkin
, Dynamics of magnetic domain walls under their own inertia. Science 330, 1810–1813 (2010).
V. L. Sobolev,
H. L. Huang,
S. C. Chen
, Domain wall dynamics in the presence of an external magnetic field normal to the anisotropy axis. J. Magn. Magn. Mater. 147, 284–298 (1995).
J. Kaczér,
R. Gemperle
, The rotation of bloch walls. Czech. J. Phys. 11, 157–170 (1961).
L. D. Buda-Prejbeanu,
M. Miron,
, Current induced domain wall dynamics in the presence of a transverse magnetic field in out-of-plane magnetized materials. J. Appl. Phys. 112, 053901 (2012).
P. Agrawal,
D. C. Bono,
, Spin Hall torque magnetometry of Dzyaloshinskii domain walls. Phys. Rev. B 90, 184427 (2014).
A. A. Thiele
, Steady-state motion of magnetic domains. Phys. Rev. Lett. 30, 230–233 (1973).
K. Xia,
P. J. Kelly,
G. E. W. Bauer,
A. Brataas,
I. Turek
, Spin torques in ferromagnetic/normal-metal stuctures. Phys. Rev. B 65, 220401 (2002).
J. Torrejon,
, Interface control of the magnetic chirality in CoFeB/MgO heterostructures with heavy-metal underlayers. Nat. Commun. 5, 4655 (2014).
R. Lo Conte,
A. Hrabec,
A. Lamperti,
T. Schulz,
L. Nasi,
L. Lazzarini,
R. Mantovan,
F. Maccherozzi,
S. S. Dhesi,
B. Ocker,
C. H. Marrows,
T. A. Moore,
M. Kläui
, Role of B diffusion in the interfacial Dzyaloshinskii-Moriya interaction in Ta/Co20Fe60B20/MgO nanowires. Phys. Rev. B 91, 014433 (2015).
I. Gross,
L. J. Martínez,
J.-P. Tetienne,
T. Hingant,
J.-F. Roch,
K. Garcia,
R. Soucaille,
J. P. Adam,
V. Jacques
, Direct measurement of interfacial Dzyaloshinskii-Moriya interaction in X|CoFeB|MgO heterostructures with a scanning NV magnetometer (X = Ta, TaN, and W). Phys. Rev. B 94, 064413 (2016).
Funding: This work was supported by the National Research Foundation (NRF), Prime Minister's Office, Singapore, under its Competitive Research Programme (CRP award no. NRFCRP12-2013-01). K.-J.L. was supported by the NRF of Korea grant funded by the Korea government (MSIP) (2011–0027905, 2015M3D1A1070465). Author contributions: J.Y., J.H.K., and H.Y. initiated this work. J.Y. and X.Q. deposited the films. J.Y., J.H.K., and J.S. fabricated devices. J.Y. performed the switching measurements. J.M.L. characterized the films. S.-W.L., J.Y., and K.-J.L. performed theoretical and numerical studies. All authors discussed the results. J.Y., S.-W.L., K.-J.L., and H.Y. wrote the manuscript. H.Y. supervised and led the project. Competing interests: The authors declare that they have no competing interests. Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. Additional data related to this paper may be requested from the authors.
Copyright © 2017, The Authors
You are going to email the following Anomalous spin-orbit torque switching due to field-like torque–assisted domain wall reflection
By Jungbum Yoon, Seo-Won Lee, Jae Hyun Kwon, Jong Min Lee, Jaesung Son, Xuepeng Qiu, Kyung-Jin Lee, Hyunsoo Yang
Science Advances 21 Apr 2017 : e1603099
The switching probability of spin-orbit torque devices is controlled by the field-like torque, and switching back can occur.

redpajama_set_name: RedPajamaCommonCrawl


text:
Nickel ist ein chemisches Element mit dem Elementsymbol Ni und der Ordnungszahl 28. Es zählt zu den Übergangsmetallen, im Periodensystem steht es nach der älteren Zählweise in der 8. Nebengruppe oder Eisen-Platin-Gruppe, nach der neueren in der Gruppe 10 oder Nickelgruppe.

Geschichte

Nickel wurde erstmals 1751 von Axel Frederic Cronstedt rein dargestellt und nach dem Mineral Kupfernickel (schwedisch kopparnickel, heute Nickelin) benannt, in dem er das bis dahin unbekannte Metall fand.

Mit der Bezeichnung Kupfernickel belegten die mittelalterlichen Bergleute das Erz, das zwar aussah wie Kupfererz, aus dem sich aber kein Kupfer gewinnen ließ, als sei es von Berggeistern ("Nickeln") verhext. Eine ähnlich koboldhafte Etymologie findet sich bei Cobalt.

Die erste Münze aus reinem Nickel wurde 1881 geprägt.

Vorkommen
Nickel kommt in der Erdkruste mit einem Gehalt von etwa 0,008 % vor. Aufgrund geophysikalischer und geochemischer Indizien geht man davon aus, dass sich der größte Teil des Nickels auf der Erde und anderen terrestrischen Planeten im Kern befindet, wo es eine Legierung mit Eisen und einigen leichten Elementen bildet. Im Erdkern beträgt sein Massenanteil nach neuesten Modellen etwa 5,2 %.

Gediegen, das heißt in elementarer Form, kommt Nickel nur selten vor. Bisher sind rund 50 Fundorte für gediegenes Nickel dokumentiert (Stand 2018), so unter anderem in Australien, China, Kanada, Russland und den Vereinigten Staaten von Amerika.

Traditionell wird der größte Teil der Nickelproduktion aus sulfidischen Erzen wie Pentlandit (ca. 34 % Nickel), Nickelmagnetkies (Verwachsungsaggregat aus Pyrrhotin und Pentlandit) sowie einigen weiteren Nickelmineralen wie Millerit (ca. 64–65 % Nickel) und Nickelin (ca. 44 % Nickel) gewonnen. Darüber hinaus werden auch lateritische Nickelerze, vor allem aus Garnierit, einem Gemenge aus Népouit (ca. 46 % Nickel) und Willemseit (ca. 29 % Nickel), als Rohstoffe zur Nickelproduktion abgebaut. Insgesamt sind bisher rund 200 Nickelminerale bekannt, und einige haben noch weit höhere Nickelgehalte als die bereits genannten, kommen jedoch im Gegensatz zu diesen viel seltener vor. So ist beispielsweise der sehr seltene Bunsenit das Mineral mit dem höchsten Nickelgehalt von bis zu 78,58 %. Die ebenfalls seltenen Minerale Heazlewoodit und Awaruit enthalten zwischen 72 und 73 % Nickel.

Die Gewinnung verschiebt sich aufgrund der Ausbeutung der klassischen sulfidischen Lagerstätten zunehmend zu lateritischen Nickelerzen. Diese müssen jedoch aufwändig per Hochdruck-Säurelaugung () gewonnen werden.

Abbau

Um das Nickel wirtschaftlich abbauen zu können, muss der Nickelgehalt des Erzes mindestens 0,5 % betragen. Die wichtigsten Vorkommen finden sich in Kanada (Sudbury-Becken), Neukaledonien, Russland (Norilsk und Halbinsel Kola), Australien (Queensland) und Kuba (Moa Bay und Nicaro). Ein häufiger Begleiter des Nickels ist Cobalt. Eine immer größere Rolle spielt auch bei Nickel Recycling aus diversen nickelhaltigen Abfällen. 2021 betrug der Anteil von Nickel aus Recycling in den USA bereits 52 %.

Nickel als Mineral
Natürlich vorkommendes Nickel in seiner elementaren Form wurde erstmals 1967 durch Paul Ramdohr beschrieben und von der International Mineralogical Association (IMA) als eigenständige Mineralart anerkannt (Interne Eingangs-Nr. der IMA: 1966-039).

Gemäß der Systematik der Minerale nach Strunz (9. Auflage) wird Nickel unter der System-Nr. 1.AA.05 (Elemente – Metalle und intermetallische Verbindungen – Kupfer-Cupalit-Familie – Kupfergruppe) beziehungsweise in der veralteten 8. Auflage unter I/A.04b (Nickel-Reihe) eingeordnet. Die vorwiegend im englischsprachigen Raum verwendete Systematik der Minerale nach Dana führt das Element-Mineral unter der System-Nr. 01.01.11.05 (Eisen-Nickelgruppe).

Als Typlokalität gilt die Halbinsel Bogota nahe Canala in der Nordprovinz von Neukaledonien, wo sich gediegen Nickel in Form idiomorpher kubischer Körner oder eingewachsener Würfel bis etwa 0,1 mm als Einschlüsse in Heazlewoodit sowie als "spinnenartige" unregelmäßige Masse zwischen den Heazlewooditkörnern fand. Als Begleitminerale können neben Heazlewoodit unter anderem noch Chalkopyrit, Chalkosin, Galenit, Godlevskit, gediegen Kupfer, Millerit, Orcelit, Pentlandit, Pyrit und Pyrrhotin auftreten.

Gewinnung und Darstellung

Darstellung des Kupfer-Nickel-Feinsteins
Der überwiegende Teil des Nickels wird aus nickel- und kupferhaltigen Eisenerzen wie Nickelmagnetkies gewonnen. Um die Gewinnung wirtschaftlich zu machen, muss das Nickel zunächst durch Flotation auf etwa fünf Prozent Nickelgehalt angereichert werden. Danach wird das Erz ähnlich wie bei der Kupferherstellung geröstet. Dabei wird das Erz zunächst vorgeröstet, um einen Teil des Eisensulfids in Eisenoxid umzuwandeln. Anschließend werden Silikate und Koks dazugegeben, um das Eisenoxid als Eisensilicat zu verschlacken. Gleichzeitig bildet sich der Kupfer-Nickel-Rohstein aus Nickel-, Kupfer- und Eisensulfid. Da dieser spezifisch schwerer als die Eisensilicat-Schlacke ist, können die beiden Phasen getrennt abgestochen werden.

Anschließend wird der Rohstein in einen Konverter gefüllt und Siliciumdioxid dazugegeben. Es wird Sauerstoff eingeblasen. Dadurch wird das restliche Eisensulfid zu Eisenoxid geröstet und danach verschlackt. Es entsteht der Kupfer-Nickel-Feinstein, der zu etwa 80 % aus Kupfer und Nickel und zu etwa 20 % aus Schwefel besteht.

Gewinnung von Rohnickel
Zur Gewinnung des Rohnickels muss das Nickel vom Kupfer abgetrennt werden. Dazu verschmilzt man den Feinstein mit Natriumsulfid Na2S. Dabei bildet sich nur zwischen Kupfer- und Natriumsulfid ein leicht schmelzendes Doppelsulfid. Es bilden sich zwei einfach zu trennende Phasen aus Kupfer-Natrium-Doppelsulfid (flüssig) und Nickelsulfid. Nach der Abtrennung wird das Nickelsulfid zu Nickeloxid geröstet und danach mit Koks zu Nickel reduziert.

Gewinnung von Rein- und Reinstnickel

Um Reinnickel zu gewinnen, wird das Rohnickel elektrolytisch raffiniert. Dazu wird in einer Elektrolysezelle das Rohnickel als Anode, ein Nickelfeinblech als Kathode geschaltet. Als Elektrolyt dient eine Nickelsalzlösung. Während der Elektrolyse gehen an der Anode Nickel und alle unedleren Bestandteile in Lösung. Alle edleren Bestandteile bleiben fest und fallen als Anodenschlamm unter die Elektrode. Dieser dient als wichtige Quelle für die Herstellung von Edelmetallen wie Gold oder Platin. An der Kathode werden Nickelionen aus der Lösung zu Nickel reduziert, alle unedleren Bestandteile bleiben in Lösung. Die Reinheit von Elektrolytnickel beträgt rund 99,9 %.

Für die Gewinnung von Reinstnickel mit einer Reinheit von 99,99 % gibt es als Spezialverfahren das Mond-Verfahren, benannt nach Ludwig Mond, der 1890 Nickeltetracarbonyl entdeckte. Dieses Verfahren beruht auf der Bildung und Zersetzung des Nickeltetracarbonyls. Dazu wird feinverteiltes Rohnickelpulver bei 80 °C in einen Kohlenmonoxidstrom gebracht. Dabei bildet sich gasförmiges Nickeltetracarbonyl. Dieses wird von Flugstaub befreit und in eine 180 °C heiße Zersetzungskammer geleitet. Darin befinden sich kleine Nickelkugeln. An diesen zersetzt sich das Nickeltetracarbonyl wieder zu Nickel und Kohlenmonoxid. Es entsteht dadurch sehr reines Nickel.
Ni_{(s)} {+} 4CO_{(g)} <=> Ni(CO)4_{(g)}

Labordarstellung
Zur Darstellung kleinerer Mengen sehr reinen Nickels im Labor existieren unterschiedliche Verfahren:

 Reduktion des Oxids mit Wasserstoff bei 150 °C bis 250 °C:
NiO + H2 -> Ni + H2O

 Reduktion einer Nickel(II)-chlorid-Suspension in Diethylether über eine Grignard-Reaktion

 Thermische Zersetzung von Nickel(II)-oxalat in Abwesenheit von Sauerstoff:
NiC2O4 ->[T][] Ni + 2 CO2

 Reduktion von Nickel(II)-chlorid mit einer Natriumdispersion:
NiCl2 + 2 Na -> Ni + 2 NaCl

Insbesondere die Thermolyse des Oxalats liefert fein verteiltes pyrophores Nickelpulver.

Eigenschaften

Physikalische Eigenschaften

Nickel ist ein silbrig-weißes Metall, das mit einer Dichte von 8,91 g/cm³ zu den Schwermetallen zählt. Es ist mittelhart (Mohs-Härte 3,8), schmiedbar, duktil und lässt sich ausgezeichnet polieren. Nickel ist wie Eisen und Cobalt ferromagnetisch, wobei die Curie-Temperatur 354 °C beträgt. Das Metall kristallisiert in einer kubisch-flächenzentrierten Kristallstruktur (Kupfer-Typ) in der  mit dem Gitterparameter a = 352,4 pm sowie vier Formeleinheiten pro Elementarzelle. Diese Struktur behält es auch bei hohen Drücken bis mindestens 70 GPa bei. Eine weitere metastabile Modifikation mit kubisch-raumzentrierter Kugelpackung konnte in dünnen Schichten auf Eisen oder Galliumarsenid gewonnen werden. Sie besitzt mit 183 °C eine deutlich geringere Curie-Temperatur.

Die Zugfestigkeit von weichgeglühtem Nickel liegt bei 400–450 MPa bei einer Bruchdehnung zwischen 30 und 45 %. Die Härtewerte liegen um die 80 HB. Kalt verfestigtes Nickel, dessen Bruchdehnung unter 2 % beträgt, erreicht Festigkeiten bis 750 MPa bei Härtewerten um 180 HB. Reinnickelhalbzeuge mit 99 % Ni-Gehalt können kalt hochverfestigt werden.

Das Isotop 62Ni hat die höchste Bindungsenergie je Nukleon aller Isotope aller Elemente.

Chemische Eigenschaften
Nickel ist in kompakter Form bei Raumtemperatur gegen Luft, Wasser, Salzsäure und Laugen sehr beständig und nicht brennbar. Verdünnte Säuren greifen Nickel nur sehr langsam an. Gegenüber konzentrierten oxidierenden Säuren (Salpetersäure) tritt analog zum rostfreien Stahl Passivierung ein. Löslich ist Nickel in verdünnter Salpetersäure (ca. 10- bis 15-prozentig). Auch eine halbkonzentrierte Salpetersäure (ca. 30-prozentig) bewirkt noch merkliche Passivierung. Der häufigste Oxidationszustand ist +II, seltener werden −I, 0, +I, +III und +IV beobachtet. Im Nickeltetracarbonyl hat Nickel die Oxidationszahl 0. Nickel(II)-Salze lösen sich in Wasser unter Bildung von Aquakomplexen mit grünlicher Farbe.

Fein verteiltes Nickelpulver kann durch kurzzeitige Einwirkung einer Zündquelle leicht entzündet werden und brennt nach deren Entfernung weiter. Die Entzündungsgefahr ist umso größer, je feiner der Stoff verteilt ist.
Fein verteiltes Nickel reagiert mit Kohlenmonoxid bei 50 bis 80 °C zu Nickeltetracarbonyl, Ni(CO)4, einer farblosen, sehr giftigen Flüssigkeit. Diese dient als Zwischenprodukt zur Herstellung von reinstem Nickel nach dem Mond-Verfahren. Bei 180 bis 200 °C zerfällt Nickeltetracarbonyl wieder in Nickel und Kohlenmonoxid.

Physiologie
Der umstrittenen Essenzialität von Nickel steht die Existenz mehrerer Enzyme gegenüber, die im Normalfall Nickel enthalten, darauf aber nicht angewiesen sind, da dessen Rolle als Kation von anderen zweiwertigen Kationen übernommen werden kann. Im Menschen handelt es sich dabei um drei Proteine, von denen bekannt ist, dass sie Nickel binden:
 alpha-Fetoprotein bindet Nickel, ist aber nicht darauf angewiesen, da kein Enzym
 Aciredukton-Dioxygenase, ein Enzym des Methionin-Salvage-Stoffwechselwegs, das üblicherweise Nickel oder ein anderes zweiwertiges Kation bindet
 Polyribonukleotid-5′-hydroxylkinase Clp1, die als Cofaktor Magnesium, Mangan oder Nickel benötigt

Für Pflanzen und verschiedene Mikroorganismen ist die Essenzialität von Nickel durch Isolierung mehrerer Enzyme (z. B. Urease, Co-F430), die Nickel im aktiven Zentrum enthalten, sowie durch Nachweis von Mangelerscheinungen in nickelarmer Umgebung, die sich durch Zusatz von Ni(II)-Salzen beheben lassen, gesichert.

In der Elektrophysiologie werden Nickel-Ionen dazu verwendet, spannungsaktivierte Calciumkanäle zu blockieren.

Gesundheitliche Probleme
Nickel ist mit der Nickeldermatitis der häufigste Auslöser für Kontaktallergien: In Deutschland sind schätzungsweise 1,9 bis 4,5 Millionen Menschen gegen Nickel sensibilisiert. Wegen daher geänderter Gesetzgebung sind Metalle und Legierungen, die mit der Haut in Kontakt kommen, seltener vernickelt. Etwa 10 % aller Kinder sind gegenüber Nickel sensibilisiert. Bei erneutem Kontakt mit dem Allergen können diese mit einer Kontaktallergie reagieren. Außerdem ist ein erhöhter Nickelgehalt in der Atemluft und im Trinkwasser ein Risikofaktor für eine Sensibilisierung gegen Nickel bei Kindern.

Die tolerierbare tägliche Aufnahmemenge (TDI) von Nickel beträgt laut Europäischer Behörde für Lebensmittelsicherheit (EFSA) 2,8 Mikrogramm (0.0028 Milligramm) pro Kilogramm Körpergewicht. 2019 hat die Arbeiterkammer Oberösterreich zwölf verschiedene Sojadrinks bei der Agentur für Gesundheit und Ernährungssicherheit untersuchen lassen. Die Werte lagen zwischen 0,25 (Dennree Soja Drink Natur) und 0,69 Milligramm pro Liter (Ja! Natürlich Bio Soja Drink). Bei der Sojamilch mit den höchsten Werten hat ein 30 Kilo schweres Kind bereits bei einem Viertelliter mehr als doppelt so viel Nickel aufgenommen wie von der EFSA empfohlen.

Das Einatmen anorganischer Nickelverbindungen ist mit einem erhöhten Krebsrisiko für Plattenepithelkarzinome der Lunge und der oberen Luftwege verbunden. Derartige bösartige Neubildungen werden in Deutschland bei berufsbedingter Exposition als Berufskrankheiten anerkannt (BK 4109).

Verbote
Zur Eindämmung der Risiken einer Nickelempfindlichkeit und einer Wirkung als Allergen verlangte die Europäische Union 1994 von ihren Mitgliedstaaten Regelungen zur Begrenzung der Verwendung und des Inverkehrbringens von Produkten aus Nickel oder Nickelverbindungen, die unmittelbar und länger mit der menschlichen Haut in Verbindung kommen wie Ohrstecker, Armbanduhrgehäuse, Halsketten, Brillengestelle oder Reißverschlüsse als Teil der Bekleidung; als Grenzwert war eine Nickelabgabe (Nickellässigkeit) von mehr als 0,5 Mikrogramm je Quadratzentimeter und Woche bestimmt, die auch bei einem beschichteten Erzeugnis aus Nickel nach zwei Nutzungsjahren nicht überschritten werden durfte. In Deutschland wurden diese Verbote durch die Bedarfsgegenständeverordnung für Bedarfsgegenstände, also Gegenstände mit Hautkontakt oder mit Lebensmitteln, umgesetzt und später durch Kennzeichnungsgebote ergänzt. Die Verwendung von Nickel und das Inverkehrbringen solcher Erzeugnisse ist in der Europäischen Union seit 2009 unmittelbar wirksam geregelt. Demnach gilt weiterhin der Grenzwert (Migrationslimit) von 0,5 μg/(cm² Woche), bei Stäben, die in die Haut gestochen werden (Ohrstecker, Piercings), jedoch nun von 0,2 μg/(cm² Woche). In der Praxis kann allerdings unklar sein, was "längerer" Hautkontakt konkret bedeutet, etwa zur Beurteilung von Spielzeug, Nähnadeln oder Schreibstiften.

Verwendung

Nickel wird als Metall in geringen Mengen benötigt, der größte Teil der Produktion geht in die Produktion von nichtrostenden Stählen und Nickellegierungen. Nickel wird in vielen spezifischen und erkennbaren Industrie- und Konsumgütern verwendet, einschließlich Edelstahl, Alnico-Magneten, Münzen, wiederaufladbaren Batterien, E-Gitarrensaiten, Mikrofonkapseln, Plattierungen auf Sanitärarmaturen und speziellen Legierungen wie Permalloy, Elinvar und Invar. Es wird zum Beschichten und als Grüntönung in Glas verwendet. Die Reserven an nach heutigen Gesichtspunkten abbauwürdigen Nickelvorkommen liegen zwischen 70 und 170 Millionen Tonnen. Gegenwärtig werden weltweit jährlich mehr als zwei Millionen Tonnen (2020: 2,5 Mio. Tonnen) gefördert. Der Preis für Nickel unterliegt wegen Finanzmarktspekulationen zeitweise sehr hohen Preisschwankungen.

Verwendung als Metall

Reines Nickelmetall wird in feinverteilter Form als Katalysator bei der Hydrierung ungesättigter Fettsäuren verwendet. Auf Grund seiner chemischen Beständigkeit wird Nickel für Apparate im chemischen Labor und der chemischen Industrie verwendet (z. B. Nickeltiegel für Aufschlüsse). Aus Nickelmetall werden Nickellegierungen, z. B. für Münzen, hergestellt.

Nickel dient als Überzugsmetall zum Korrosionsschutz ("Vernickeln") von Metallgegenständen: Wegen seiner vor Oxidation schützenden Eigenschaften werden Metalle (insbesondere Eisen) mittels galvanischer Technik für bestimmte technische Zwecke mit einer Nickelschicht überzogen.

Ebenfalls genutzt wurde das Metall früher zur Herstellung der Fassungen von Nickelbrillen.

Als Betastrahler wird das Nickelisotop 63Ni in Elektroneneinfangdetektoren in Gaschromatografen eingesetzt.

Verwendung als Legierung

Nickel ist ein bedeutendes Legierungsmetall, das hauptsächlich zur Stahlveredelung verwendet wird. Der größte Teil des Nickels geht dorthin. Es macht Stahl korrosionsbeständig und erhöht seine Härte, Zähigkeit und Duktilität. Mit Nickel hochlegierte Stähle werden in besonders korrosiven Umgebungen eingesetzt. Der Edelstahl V2A (der Name entstammt der "Versuchscharge 2 austenitisch" im Krupp-Stahlwerk, entspricht X12CrNi18-8) enthält 8 % Nickel neben 18 % Chrom, V4A (Markennamen Cromargan oder Nirosta) 11 % neben 18 % Chrom und 2 % Molybdän.

Nickel ist ein ausgezeichnetes Legierungsmittel für bestimmte Edelmetalle und wird im Brandtest als Sammler von Elementen der Platinmetalle verwendet. Als solches ist Nickel in der Lage, alle sechs Platinmetalle, vor allem Platin und Palladium, vollständig aus Erzen zu sammeln und Gold teilweise zu sammeln.

Nickelschaum oder Nickelnetz wird in Gasdiffusionselektroden für alkalische Brennstoffzellen verwendet.

Nickel und seine Legierungen werden häufig als Katalysatoren für Hydrierungsreaktionen verwendet. Raney-Nickel, eine feinteilige Nickel-Aluminium-Legierung, ist eine gebräuchliche Form, obwohl auch verwandte Katalysatoren verwendet werden, einschließlich Katalysatoren vom Raney-Typ.

Etwa 20 % des Nickels werden (in Deutschland) zur Herstellung von weiteren Nickellegierungen verwendet:

 Konstantan, eine Legierung aus 55 % Kupfer und 45 % Nickel, die über einen großen Temperaturbereich einen annähernd konstanten spezifischen elektrischen Widerstand besitzt. Sie wird vor allem für genaue Widerstände verwendet.
 Nickelbasis-Superlegierungen sind Legierungen speziell für den Einsatz bei hohen Temperaturen und unter korrosiven Medien. Sie finden zum Beispiel in Flugzeugturbinen und Gasturbinen von Kraftwerken Anwendung.
 Raney-Nickel, eine Nickel-Aluminium-Legierung, die ein wichtiger Katalysator für die Hydrierung organischer Verbindungen ist.
 Neusilber, eine Kupfer-Nickel-Zink-Legierung mit 10–26 % Nickelanteil, die besonders korrosionsbeständig ist und hauptsächlich für Bestecke und elektrotechnische Geräte verwendet wird.
 Monel, ebenfalls eine Kupfer-Nickel-Legierung mit etwa 65 % Nickel, 33 % Kupfer und 2 % Eisen, die sich durch besondere chemische Beständigkeit, unter anderem gegen Fluor, auszeichnet. Sie wird deshalb für Fluor-Druckgasflaschen verwendet.
 Austenitisches Gusseisen mit Kugelgraphit, ein sphärolithisches Sondergusseisen mit bis zu 20 % Nickel, für den Einsatz in korrosiver Umgebung und bei hohen Temperaturen.

Nachweis

Die Nachweisreaktion für die in Wasser meist mit grüner Farbe löslichen Nickel(II)-salze wird in der quantitativen Analytik gravimetrisch sowie qualitativ im Kationentrenngang mit Dimethylglyoxim-Lösung (Tschugajews Reagens) durchgeführt. Nickelsalze werden zuvor gegebenenfalls durch Ammoniumsulfid als grauschwarzes Nickel(II)-sulfid ausgefällt und in Salpetersäure gelöst. Der spezifische Nachweis ist dann durch Reaktion mit Dimethylglyoxim in ammoniakalischer Lösung möglich. Dabei fällt das himbeerrote Bis(dimethylglyoximato)nickel(II) als Komplex aus:

Ni^2+ + 2C4H8N2O2 + 2H2O -> Ni(C4H7N2O2)2 v + 2H3O+.

Da Nickel aus ammoniakalischer Lösung mit Dimethylglyoxim quantitativ ausfällt, ist dieser Nachweis auch für die quantitative gravimetrische Nickelanalyse verwendbar. Aus ammoniakalischer Lösung kann auch mittels Elektrogravimetrie an einer Platinnetzelektrode eine quantitative Bestimmung erfolgen. Ähnlich anderen Schwermetallen wird Nickel heute meist durch Atomspektroskopie oder Massenspektrometrie auch im Ultraspurenbereich quantitativ bestimmt. Äußerst empfindlich ist die inverse Voltammetrie mit adsorptiver Anreicherung des Ni-Dimethyglyoxim-Komplexes an hängenden Quecksilbertropfen oder Quecksilberfilmelektroden.

Verbindungen
Nickel kommt in Verbindungen hauptsächlich in der Oxidationsstufe +II vor. Die Stufen 0, +I, +III und +IV sind selten und meist instabil. Nickel bildet eine Vielzahl meist farbiger Komplexe.

Oxide
Nickel(II)-oxid und Nickel(III)-oxid sind grüne beziehungsweise schwarze Feststoffe und werden zur Herstellung von Keramik, Gläsern und Elektroden verwendet. Außerdem werden sie als Katalysatoren für die Hydrierung organischer Verbindungen genutzt. Wie viele andere binäre Metalloxide ist Nickel(II)-oxid häufig nicht stöchiometrisch, was bedeutet, dass das Nickel-Sauerstoffverhältnis von 1:1 abweicht. Diese Eigenschaft geht mit einer Farbänderung einher, wobei das stöchiometrisch korrekte Nickel(II)-oxid grün und das nichtstöchiometrische Nickel(II)-oxid schwarz ist. Nickel(III)-oxid wirkt stark oxidierend und ist als Reinstoff unbekannt.

Halogenide
Nickel(II)-chlorid ist ein gelber, stark hygroskopischer Feststoff, der als Farbstoff für Keramik und zur Herstellung von Nickelkatalysatoren dient. Neben der wasserfreien Form gibt es noch wasserhaltige Nickel(II)-chloride, z. B. das grüne Nickel(II)-chlorid-Hexahydrat, das aus wässrigen Nickelchloridlösungen auskristallisiert. Das wasserfreie Nickel(II)-chlorid hat eine trigonale Kristallstruktur vom Cadmium(II)-chlorid-Typ mit der . Das Hexahydrat kristallisiert im monoklinen Kristallsystem in der .

Nickel(II)-fluorid ist ebenfalls stark hygroskopisch und bildet gelbliche bis grüne tetragonale Kristalle. Im Gegensatz zu vielen Fluoriden ist es an der Luft stabil. Es kristallisiert im tetragonalen Kristallsystem mit der . Das Tetrahydrat kristallisiert im orthorhombischen Kristallsystem mit der .

Weitere anorganische Nickelverbindungen

Nickel(II)-hydroxid und Nickel(III)-oxidhydroxid dienen zur Speicherung elektrischer Energie in Nickel-Cadmium- und anderen Nickelakkumulatoren.

Nickel(II)-nitrat verwendet man in der Keramikindustrie als braunes Pigment, in der Färberei als Beizmittel, zum elektrolytischen Vernickeln, zum Gewinnen von Nickel(II)-oxid und zum Herstellen von reinem Katalysatornickel. Nickel(II)-nitrat ist ein starkes Oxidationsmittel und kommt gewöhnlich in Form seines Hexahydrates Ni(NO3)2 · 6 H2O vor.

Nickel(II)-sulfat und Ammoniumnickel(II)-sulfat werden bei der Galvanisierung (Vernickelung) verwendet. Nickel(II)-sulfat ist die technisch wichtigste Nickelverbindung. Es dient zur Herstellung von anderen Nickelverbindungen und Katalysatoren. Die wässrigen Lösungen von Nickel(II)-sulfat und Nickel(II)-chlorid werden zur galvanischen Abscheidung von metallischen Nickelschichten verwendet. Weiterhin wird es in der Färberei als Beizmittel und bei der Herstellung von Gasmasken verwendet.

Nickel(II)-carbonat kommt in mehreren Hydratformen vor. Es wird als Katalysator bei der Fetthärtung und zur Herstellung von Nickel(II)-oxid, keramischen Farben (Pigment) und Glasuren sowie beim Galvanisieren verwendet. Es bildete ein trigonales Kristallsystem mit der .

Nickel(II)-sulfid fällt aus ammoniakalischen, nicht jedoch aus sauren, nickelhaltigen Lösungen mit Ammoniumsulfid aus. Dadurch kann Nickel mit der Ammoniumsulfid-Gruppe im Kationentrennungsgang abgetrennt werden.

Das als Breithauptit bekannte Nickelantimonid ist ein metallisch glänzendes Mineral und hat eine helle kupferrote Farbe. Anwendung findet Nickelantimonid als Werkstoff in magnetischen Feldplatten, wo es zwischen magnetisch empfindlichen Schichten aus Indiumantimonid eingebracht wird. Magnetische Feldplatten ändern in Abhängigkeit von der magnetischen Flussdichte ihren elektrischen Widerstand und dienen als Sensor für Magnetfelder. Es bildet eine hexagonale Kristallstruktur in der .

Organische Nickelverbindungen
Nickeltetracarbonyl Ni(CO)4 ist eine farblose, sehr giftige Flüssigkeit. Sie ist ein wichtiges Zwischenprodukt im Mond-Verfahren. Nickeltetracarbonyl war die erste entdeckte Metallcarbonyl-Verbindung.

Nickelkomplexe

Nickel und dabei v. a. Nickel(II)-Ionen bildet viele, meist farbige Komplexe. Die Koordinationszahlen 6, 5 oder 4 sind am häufigsten. Bei schwachen, einzähnigen Liganden, beispielsweise Wasser, liegen sie meist als oktaedrische und paramagnetische High-spin-Komplexe mit Koordinationszahl 6 vor. Starke Liganden wie Cyanid bilden quadratisch-planare, diamagnetische Low-spin-Komplexe. Ebenfalls einen quadratisch-planaren Komplex bildet Dimethylglyoxim, da der Komplex zusätzlich durch Wasserstoffbrücken stabilisiert ist. Letzterer Bis(dimethylglyoximato)nickel(II)-Komplex ist für den nasschemischen Nickelnachweis von Bedeutung.
Anionische Nickelkomplexe enden auf "-niccolat".

Beispiele für Amminkomplexe sind der blaue Tetraamminnickel(II)- und violette Hexaamminnickel(II)-komplex. Beide Verbindungen erhält man durch Zugabe von Ammoniak zu Nickel(II)-salzlösungen:
NiSO4 + 4NH4+ + 4OH- -> [Ni(NH3)4]SO4 + 4H2O
Durch Zugabe von Kaliumcyanid zu Nickel(II)-salzlösungen entsteht zunächst Nickel(II)-cyanid, das sich im Überschuss von Kaliumcyanid zu gelbem Kaliumtetracyanoniccolat(II) auflöst:
Ni(CN)2 + 2KCN -> K2[Ni(CN)4]
Eine entsprechende Verbindung entsteht mit Kaliumthiocyanat. Eine sehr empfindliche Verbindung ist das Kaliumhexafluoroniccolat(IV) (K2[NiF6]).
Mit einem starken Reduktionsmittel lässt sich aus Kaliumtetracyanoniccolat(II) der zweikernige Komplex K4[Ni2(CN)6] mit einwertigem Nickel herstellen.
Daneben existiert eine Vielzahl von Komplexen mit organischen Liganden wie beispielsweise Ethylendiamin oder Anionen von Carbonsäuren.

Literatur
 Eberhard Auer, Siegfried Müller, Rainer Slotta: 250 Jahre Nickel. Vom "nickel" zum "EURO". Verlag Deutsches Bergbau-Museum, Reihe Veröffentlichungen aus dem Deutschen Bergbau-Museum Bochum Bd. 95, Bochum 2001, ISBN 3-921533-81-3.

 Harry H. Binder: Lexikon der chemischen Elemente – das Periodensystem in Fakten, Zahlen und Daten. Hirzel, Stuttgart 1999, ISBN 3-7776-0736-3.
 VDM-Magazin Nr. 708, Themenheft Nickel, November 2022

Weblinks

 Mineralienatlas:Nickel (Wiki)
 Reinstnickel >=99,9 % als Bild in der Sammlung von Heinrich Pniok
 Nickelpreisentwicklung als Diagramm (englisch)
 Medizinischer Text über Nickelmangel oder -überschuss im Körper der eesom AG, Bern (CH).

Einzelnachweise

Coenzym
Mineral
Kubisches Kristallsystem
Elemente (Mineralklasse)
Metallischer Werkstoff
Magnetwerkstoff
Beschränkter Stoff nach REACH-Anhang XVII

redpajama_set_name: RedPajamaWikipedia


text:
Jr's West End
Jr's West End Restaurants Near Me | Long Branch, New Jersey, 07740 | Reviews, Local Offers
75 Brighton Ave Ste D, Long Branch, NJ 07740
Website: http://jrsdelivers.com/
75 Brighton Ave Ste D
Long Branch, New Jersey, 07740
Monday 11:00am 3:00am
Tuesday 11:00am 3:00am
Wednesday 11:00am 3:00am
Thursday 11:00am 4:00am
Friday 11:00am 4:00am
Saturday 11:00am 4:00am
Sunday 11:00am 3:00am
Jr's West End's See Inside Tour
Jr's West End's Street View
Jr's West End Reviews
Visit http://m.localtunity.com/jrswestend on your phone to get the app
http://jrsdelivers.com/


text:
12. 13. 16 / by Patrick Caughill
Universal Basic Income Doesn't Just Improve Your Finances, It Improves Your Health
Fewer money worries leads to fewer health conditions.
12. 13. 16 / Patrick Caughill
Image by Stefan Bohrer-Wikimedia
Health in Security
Universal basic income (UBI) — a system in which a population is given a set amount of money, unconditionally — is rapidly becoming a topic of increased interest across the world. Proponents expect such a system to reduce poverty and improve the economy, and now, according to some re-examined data, there may be a link between increased physical and mental health and the financial security that results from a UBI system.
For four years, in the small Canadian town of Dauphin, residents making less than $13,800 annually were given $4,800 per year to supplement their income. During this time, the population saw a decline in the number of mental health-related visits to the doctor and fewer hospital admissions due to "accident and injury," as well as few mental health diagnoses in general. These findings were also corroborated by a similar program implemented nearly two decades later on Cherokee land in the United States.
Photo credit: Joe Raedle/Newsmakers
Threat of Automation
Even more so than outsourcing, innovation in the fields of robotics and artificial intelligence is a major threat to the working-class families of the world. Experts say that not only is a UBI system necessary, it is also inevitable. As machines become cheaper and better suited for a wider variety of jobs, these low-skill workers will have increasingly fewer options to earn a living.
UBI pilot programs are being planned in Finland, Canada, the Netherlands, and even Uganda, but there is no uniformity in how these plans would be implemented. Some may opt for income restrictions, while others for truly universal implementation. However they are structured, freeing up individuals from the burden and stress of financial instability not only seems likely to make them healthier, it could lead to a spark in creativity, entrepreneurship, and innovation as well.
The Pope Just Endorsed Universal Basic Income
This Company Is Paying People $1,830 to Film Them Constantly
Basic Income Recipients Spent the Money on "Literal Necessities"
New Futurist Fear: "Economic Singularity" Could Kill Jobs Forever
AOC: Automation Means "More Time Enjoying the World We Live In"
1.10.22 Developments
Anti-Vaxxers Are Drinking Human Urine for Some Disgusting Reason
Just in case you thought the pandemic couldn't get any stupider.
By Tony Tran / Read More >>
1.07.22 Devices
Remember IBM's Amazing Watson AI? Now It's Desperately Trying to Sell It Off
It better not fall into the wrong hands...
By Abby Lee Hood / Read More >>
1.07.22 Studies
Hangover "Cures" Are Total Nonsense, According to Science
"The surest way of preventing hangover symptoms is to abstain from alcohol."
By Noor Al-Sibai / Read More >>


text:
WATCH world-first Russian house film crew's ISS mission, from launch to touchdown in 2 minutes
The Russian movie crew that grew to become the primary on the planet to shoot footage for a characteristic film in house has returned to Earth. RT's supercut video highlights the milestones of the 12-day mission, from coaching to touchdown.
Actress Yulia Peresild and filmmaker Klim Shipenko, the first-ever skilled movie crew in house, returned from their 12-day journey to the International Space Station (ISS) on Sunday. The Soyuz MS-18 spaceship, piloted by veteran Russian cosmonaut Oleg Novitsky, touched down safely in Kazakhstan earlier within the day.
RT's two-minute supercut video of the mission reveals the movie crew finishing a coaching course, withstanding excessive g-forces and getting accustomed to low-gravity environments. It additionally highlights the launch of the mission, docking with the ISS, engaged on board, in addition to the profitable return to Earth.
The movie crew's flight was facilitated as a collaboration between Russian TV Channel 1 and Roscosmos house company, whereas RT has offered particular protection of the mission. The objective of the mission was to movie scenes for an upcoming film known as 'The Challenge', which is ready in house. While the plot of the movie is being stored secret, it's recognized that the film is centered round a surgeon – performed by Peresild – touring to house to carry out coronary heart surgical procedure on an incapacitated cosmonaut.
Also on rt.com 'Very demanding place to film': Veteran cosmonauts converse to RT about challenges confronted by first-ever movie crew in orbit
Think your folks would have an interest? Share this story!
Gaza's few magnificence salons wrestle to satisfy demand
Paris bloodbath: 60 years on, France should face its colonial previous


text:
Military Notes
BusinessCitiesCrimeEducationHealthNationalPolitics
BuyGA
Class/Legals
Lawrenceville, GA (30045)
A steady rain this evening. Showers continuing overnight. Low near 35F. Winds WNW at 10 to 20 mph. Chance of rain 90%..
A steady rain this evening. Showers continuing overnight. Low near 35F. Winds WNW at 10 to 20 mph. Chance of rain 90%.
Berkely Lake
Georgia Gwinnett
Ed Kramer
DragonCon co-founder Ed Kramer fighting "sexually dangerous predator" label
Petition filed in Fulton Superior Court earlier this month
By Isabel Hughes
isabel.hughes@gwinnettdailypost.com
Isabel Hughes
Crime Reporter
Though he pleaded guilty to three counts of child molestation several years ago, DragonCon co-founder Ed Kramer doesn't want to be labeled a "sexually dangerous predator."
Earlier this month, Kramer, who was sentenced in 2013 to an aggregate of 20 years with the first five to be served in home confinement stemming from an arrest in 2000 for allegedly sexually assaulting three teenage boys, filed a petition in Fulton County Superior Court challenging a Dec. 15 letter from the state's Sexual Offender Registration Review Board informing him of his new classification.
The board is required by Georgia law to determine the risk level of sex offenders convicted in the state and places them into one of three categories: Level 1, which indicates a low risk for recidivism; Level 2, which indicates an intermediate risk of recidivism; or Level 3, sexually dangerous predator, which indicates a person's high probability of reoffending.
SDPs are required to wear electronic monitoring systems, such as an ankle bracelet, "for the remainder of (their) natural life" in addition to other requirements and restrictions.
Kramer's petition, which was obtained by the Daily Post, said the requirement "substantially interferes with (his) liberty and, coupled with the (predator classification's) extreme stigma and detriment to current and future employment opportunities, violates (Kramer's) constitutional and statutory rights."
At its core, however, the filing centers on a Gwinnett County District Attorney's office senior attorney, Richard Vandever, who serves on the review board.
According to the 19-page document, Vandever's role as a board member and his participation in the sex offender classification decision "was highly inappropriate and certainly violative of Georgia statutory law and the due process clauses of both the federal and State constitutions," due to the Gwinnett DA's office being "recused, in its entirety," from involvement in Kramer's case based on a habeas corpus challenge he previously brought against the courts and DA.
In October 2014, nearly 11 months after his December 2013 guilty plea, Kramer and his attorney Stephen Reba filed the habeus corpus petition, which essentially claimed that Judge Karen Beyers and District Attorney Danny Porter, who handled Kramer's criminal case, colluded to force him into the plea.
Reba said at the time his client wanted a trial and, in the months following the habeas corpus filing, all of Gwinnett's Superior Court judges recused themselves from handling the case.
The last two judges to recuse themselves, Melodie Snell Conner and Kathryn Schrader, filed their paperwork jointly in January 2015, saying that they found "no evidence or implication of any improper relationship existing between Superior Court Bench and the District Attorney's Office" but that they were recusing themselves to "avoid any appearance of impropriety."
The petition was later assigned to Piedmont Circuit Senior Superior Court Judge Robert Adams, where it remains pending.
Porter told the Daily Post on Thursday that his office hasn't been disqualified, however, which would void Kramer's argument that Vandever's role as a board member is a conflict of interest.
"The DA's Office hasn't been disqualified by any court order," Porter said. "The habeas was filed against state officers, so the (attorney general) is handling it. Kramer has moved to disqualify us from a motion to vacate his sentence in the original criminal case, but there's been no ruling."
Porter said: "Once again, Kramer is engaging in litigation based on false assertions of fact. He is a Dangerous Sexual Predator, and the classification is correct."
Kramer, a Duluth resident, co-founded DragonCon in 1987, though he has not been involved with the convention since 2000 when he was arrested for the alleged molestations.
His prosecution was delayed for years due constant legal posturing and a litany of medical issues, reportedly ranging from neck pain and hearing issues to emphysema and psoriatic arthritis, Porter previously said. In September 2011, he was arrested again after he was found in a Connecticut hotel room with a 14-year-old boy.
The stipulations of Kramer's bond prohibited him from having any unsupervised contact with a child under 16 years old and he was extradited to Gwinnett following the arrest.
Kramer remained part owner of DragonCon until July 2013, when he was bought out by the organization, four months prior to his guilty plea.
It was not immediately known if the timing was connected to the plea, though many had urged DragonCon to cut ties with the co-founder in the years following his initial arrest.
Convicted sex offender, DragonCon co-founder Ed Kramer back in jail
Convicted child molester and DragonCon co-founder Ed Kramer is back in jail, having been arrested for allegedly photographing a girl in Lawrenceville.
Sexual Offender Registration Review Board
Public And Administrative Law
Danny Porter
Stephen Reba
Karen Beyers
Isabel is a crime and health reporter for the Gwinnett Daily Post. She graduated from Emory University in 2016 with a B.A. in international studies. She is originally from the Boston area.
Follow Isabel Hughes
Get the latest business news delivered to your inbox every weekday.
Gwinnett Eats newsletter
Weekly email newsletter with the latest on eateries in Gwinnett County sprinkled with recipes.
Daily local news headlines from across Gwinnett County.
Get news alerts and breaking stories from the Gwinnett Daily Post delivered to your email.
Sports Newsletter
Daily sports headlines from across Gwinnett County, including high school, professional and college news.
Former Florida Mayor sentenced to 51 months after defrauding charity
Comme des Garçons criticized for cultural appropriation for using lace front cornrow wigs
A woman writing a novel about 'predatory older men' has been seated on the Harvey Weinstein jury
Fire displaces residents at Norcross area apartments Saturday
Abby Huntsman leaves 'The View' amid toxic culture at show and strained relationship with Meghan McCain
GOOD NEWS FROM SCHOOLS: 6 Gwinnett schools received Distinguished Title I statuses
Police ID two teenage boys who stole cars, credit cards from Gwinnett gyms while dressed as women
Barrow County Schools employee accused of having sexual relationships with students
First 100 customers at new Del Taco locations in Lawrenceville, Loganville get free tacos for a year
Lawrenceville teen charged with burglary, arson in New Year's day fire
Former Gwinnett County deputy indicted on excessive force and obstruction charges from 2018 incident
Hiking opportunities abound for Gwinnett residents at Georgia's state parks
Man dies after officer involved shooting at Lawrenceville Wendy's
Fox Theatre
660 Peachtree St NE, Atlanta, GA 30308
Gwinnett Stripers
2500 Buford Dr, Lawrenceville, GA 30043
Dennison Hearing Solutions
3511 Braselton Hwy, Dacula, GA 30019
TechFest 2020
Travel Photography Program
The Curious Incident of he Dog in the Night-Time
Dad's Garage
POLL: What's favorite pizza topping?
It's National Pizza Week. To celebrate, vote in our poll for your favorite pizza topping.
Cheese (Extra)
A meat topping not listed
A vegetable topping not listed
Gladiators rally, but come up short against South Carolina
Stevens-led Penn State dispatches No. 21 Ohio State
No. 11 Louisville fends off No. 3 Duke in Durham
Clemson LB Isaiah Simmons to enter NFL draft
725 Old Norcross Road
Good Taste Gwinnett
Generations Expo
All About Kids Expo
© Copyright 2020 Gwinnett Daily Post, 725 Old Norcross Road Lawrenceville, GA | Terms of Use | Privacy Policy


text:
State school board passes new budget
The Alabama State Board of Education approved its new budget year which begins Oct. 1. (Source: WSFA 12 News)
By Bryan Henry | September 12, 2019 at 4:58 PM CDT - Updated September 12 at 7:14 PM
MONTGOMERY, Ala. (WSFA) - The Alabama State Board of Education approved its new budget year which begins Oct. 1.
The vote was unanimous and it's ever so slightly less than last year's budget. The new budget is a little more than $33.5 million. Alabama State Board of Education Superintendent Dr. Eric Mackey says the numbers are in-line with day-to-day operations of the department.
"That's just the department operational budget from what we were appropriated from the state legislature and also what we get from federal indirect costs," said Mackey.
The bulk of the new year's budget is allotted for personnel costs which includes a 2 percent raise.
Copyright 2019 WSFA 12 News. All rights reserved.
Bryan Henry
Bryan Henry is a reporter Monday through Friday for WSFA 12 News. He joined the WSFA 12 family in November of 1995 as Assignment Editor. After a two-year stint on the desk, Bryan accepted an offer to resume his reporting career with WSFA 12 News.


text:
Who is Ashwini Bhatia - Banks Board Bureau recommended next SBI MD
BBB members interfaced with 20 contenders from several nationalised banks on May 30 for the said positions, according to an official statement
Updated May 31, 2020, 10:14 PM IST
BBB, the headhunter for state-owned banks and financial institutions, is headed by former Department of Personnel and Training Secretary B P Sharma
Ashwini Bhatia, who is currently serving as the Managing Director (MD) and CEO at SBI Mutual Fund, has emerged as a frontrunner for the post of next State Bank of India (SBI) MD by the Banks Board Bureau (BBB) on Saturday.
The governing body has also recommended the names of MV Rao and P P Sengupta for the post of MD at the Central Bank of India and Indian Overseas Bank. Rao is currently serving as Executive Director with Canara Bank while Sengupta is Deputy Managing Director (DMD) at SBI.
BBB members interfaced with 20 contenders from several nationalised banks on May 30 for the said positions, according to an official statement.
Bhatia will be appointed in place of P K Gupta who superannuated on March 31, while Rao will replace Central Bank of India MD Pallav Mohapatra, who will retire in February next year. Sengupta will replace Indian Overseas Bank MD and CEO Karnam Sekar, who retires on June 30.
With this exercise, the government has completed the process of appointment of head of PSU banks for the current fiscal year. The decision on the appointment will be taken by the Appointments Committee of the Cabinet headed by Prime Minister Narendra Modi.
BBB, the headhunter for state-owned banks and financial institutions, is headed by former Department of Personnel and Training Secretary B P Sharma.
PM Modi in 2016, approved the constitution of BBB as a body of eminent professionals and officials to make recommendations for the appointment of whole-time directors as well as non-executive chairpersons of public sector banks (PSBs).
It was also entrusted with the task of engaging with the board of directors of all PSBs to formulate appropriate strategies for their growth and development.
BBB was also asked to frame strategy discussion on consolidation based on requirement. The government wanted to encourage bank boards to restructure their business strategy and also suggest ways for their consolidation and merger with other banks.
Mann ki Baat Highlights: Follow all COVID-19 protocols more sincerely from now, says PM Narendra Modi
PM Modi's 'Mann Ki Baat' at 11 am today; focus likely on 'Unlock 1' of lockdown 5.0
Coronavirus India: Record single-day spike of 8,380 COVID-19 cases takes country's tally past 1.82 lakh
Posted by: Rupa Roy, May 31, 2020, 5:28 PM IST


For those of you who don't know, the Kielder is a half marathon… but with hills in it. Northern hills. Steep northern hills. Today, despite not feeling 100%, my beautiful African friend (we met in Africa) completed the Kielder half marathon and has raised over £700 towards Thomas' surgery and post operative physio.
Ever since the boys were first born Julie and her partner Vicky have been there, right there. It was with them that the boys shared their first smile with one another (image 1) and then a year or so later (image 2 FYI Julie is in the door way) the connection they all have with one another is clear to see.
Visiting recently the same love and laughter was shared. The same love and friendship.
Thank you for your beautiful friendship guys. Thank you for running for Thomas today.


CHARLESTON, W.Va. (AP) — A new judge has been appointed to the West Virginia Business Court Division.
Supreme Court Chief Justice Beth Walker appointed 19th Judicial Circuit Judge Shawn D. Nines to replace 13th Circuit Judge Joanna Tabit.
The 19th Circuit covers Barbour and Taylor counties. Gov. Jim Justice appointed Nines to the newly created judicial position, and he has served there since Jan. 2.
Nines will serve the remainder of Tabit's Business Court term, which ends Oct. 9.
The Business Court is a division within West Virginia's Judiciary that handles complex commercial litigation between businesses. Business Court judges maintain their own general circuit court dockets.


text:
The Chicago Flag
Home Learn Resources Architecture Dictionary The Chicago Flag
The Chicago flag, an image close to the hearts of many Chicagoans, is now 100 years old. The City Council adopted it on April 4, 1917 after a design competition held by the Chicago Municipal Flag Commission. Wallace Rice, a writer and Art Institute of Chicago lecturer on flag design, was responsible for writing the rules of the competition. After the commission reviewed more than 1,000 submitted entries, Rice eventually emerged as the winner.
Rice's design is simple, yet striking, and is full of symbolism that speaks to the history of Chicago. It consists of two light blue stripes cutting across a white background to create three white stripes alternating with the blue. The middle white band, which is thicker than the top and bottom, contains four red six-pointed stars.
The white and blue areas represent the city's physical geography. The three white bands stand for the north, west and south sides of the city, while the blue stripes are symbolic of the city's important bodies of water. The top blue band represents Lake Michigan and the north branch of the Chicago River. The bottom band represents the south branch of the Chicago River and the Chicago Sanitary and Ship Canal (which connects the river to a tributary of the Mississippi River system).
Each star stands for an event in Chicago's history. From left to right, they represent the following:
The Great Chicago Fire of 1871
The World's Columbian Exposition of 1893
The Century of Progress Exposition of 1933-34
Although today the flag has four stars, it began with just two, and people frequently present new ideas for the addition of a fifth star. The original two stars were those for the Fire and the 1893 World's Fair. The other two were added in the 1930s. In the original design, Rice aligned the two stars on the left to leave room for the addition of future stars to the right. Today the four stars are centered.
The six-pointed appearance of the stars is significant. Sovereign states usually use the five-pointed star, which makes it somewhat unsuitable for a city flag. Rice also believed that this six-pointed design had never before been seen on a flag, so according to him, this is "peculiarly and singularly a Chicago star, made by a Chicagoan for his greatly loved city."
Chicago's flag is one of the most popular and widely-recognized city flags in the country. In 2004, the North American Vexillological Association conducted an opinion survey on American city flags and Chicago's came in at number 2 of 150—second only to Washington D.C.'s flag. Found on buildings and public spaces throughout the city, the Chicago flag provides a visual detail that unites Chicago's urban environment. Next time you're out walking around, try counting how many times you spot it.
Historic Chicago
What if the Great Chicago Fire of 1871 Never Happened?


text:
Baby Health A-Z: Rotavirus And Diarrhoea
A common illness in babies, rotavirus can lead to stomach flu and become serious. Thankfully, it can be prevented and treated
Watching your baby suffering with an illness isn't nice at all, so you'll want to know exactly what's wrong with him and how you can help him get better, pronto.
If he's suffering from sickness and diarrhoea then he may have rotavirus, which is really common and in the baby-sphere equally contagious.
Luckily, it shouldn't last for too long and should clear up on its own. Here are the signs you need to look out for.
Rotavirus is a stomach bug that's the most common cause of severe diarrhoea in children. It's a viral infection that spreads mainly through poo and is really contagious, meaning that unfortunately your little one will probably get it at some point.
Babies are also more likely to catch to the virus because they touch everything you'd rather they didn't
The virus does affect adults too, but in babies it's a lot more serious as their immune systems are still developing. Babies are also more likely to catch to the virus because they touch everything you'd rather they didn't. Then put their fingers in their mouths.
Sooner or later, a tummy bug's likely to strike.
There are quite a few signs that can suggest your baby has the rotavirus.
'Symptoms including diarrhoea, vomiting, tummy ache and fever,' says Professor Mitch Blair, from the Royal College of Paediatrics and Child Health.
More serious symptoms include blood in his poo, frequent vomiting sickness and a high fever. Infrequent weeing and a rapid heartbeat are also things to watch out for – if you notice any of these then take your baby to his doctor as soon as you can.
Rotavirus can get serious, especially if your baby is vomiting and has diarrhoea, which can quickly lead to dehydration. Keep an eye out for dark wee, tiredness and a dry mouth – all signs of dehydration.
'Most children recover at home within a few days,' explains Professor Blair. 'But nearly one in five will need to see their doctor and one in 10 of these children end up in hospital as a result of complications such as extreme dehydration.'
How is it prevented?
'There is now an oral vaccine available on the NHS, to protect against four strains of the rotavirus infection,' says Professor Blair.
The vaccine, called Rotarix, is a liquid and is dropped straight into your baby's mouth. There are two doses that your baby needs, to be given between two and three months as the vaccine is only available to babies under the age of eight months.
The vaccine can prevent 74% of all rotavirus cases, about 98 per cent of severe cases and about 96 per cent of hospitalisations.
Author: Alison Coldridge Alison Coldridge
Alison Coldridge
tummy troubles
Baby Health A-Z: Flu
If that stuffiness and low mood is due to flu, there are ways to give your baby his very own duvet day
What is attachment parenting and could it work for you?
Want to raise your baby to be as close to you as possible but without a strict set of rules? Attachment parenting could be just the thing for you


Fred Mantel media productions - Wall detail of chateau de Beaumesnil.
Wall detail of chateau de Beaumesnil.
Chateau de Beaumesnil in Normandy, France. A shot from the side of the castle and the canal around.
Ancient watering place at le Bec Hellouin.


Courtesy of the Leadership newspaper - Sudden death is often described as an unanticipated death which has different causes. It comes as a shock, like a bolt from the blue.
Courtesy of Vancouver Sun - Recent media reports of otherwise healthy young people dying suddenly and inexplicably prompt painful questions about how or whether these deaths could have been prevented.
Courtesy of EurekAlert! - The Spectrum Health Hypertrophic Cardiomyopathy Program has been designated a national Center of Excellence by the Hypertrophic Cardiomyopathy Association (HCMA).
Annie Young, a school nurse at Lake Highlands Junior High in Dallas, TX. was in the middle of paperwork when two runners from a last period gym class came barreling into her clinic yelling about a collapsed student.
Courtesy of OnMedica - Direct admission to a specialist heart centre after a cardiac arrest is linked to higher chances of survival than being taken to the nearest general hospital, reveals research* published today in the European Heart Journal.
Courtesy of Cardiovascular Business - Although research has shown automated external defibrillators (AEDs) can increase survival after cardiac arrest, only 17 of 50 U.S. states required at least some of their schools install AEDs as of February 2016, according to a database analysis.
The New Zealand Resuscitation Council made the statement to clarify misconceptions that compression-only CPR, also known as 'hands-only CPR', is an acceptable alternative when being trained in basic life support and First Aid.
Courtesy of CBC News - People with higher levels of thyroid hormone in their bloodstream may be at greater risk of sudden cardiac death, even if those levels aren't abnormally high, a new study suggests.
Courtesy of Sur in English - With just a pair of hands and two fingers you can save a life: a fact that emphasises the necessity of taking swift action when someone is suffering from sudden cardiac arrest.
After 20 years of research scientists at the University of Cape Town have identified the mutations in a gene called CDH2, or cadherin 2, that's responsible for an inherited form of heart muscle disease that affects the right side of the heart in a condition known as cardiomyopathy.
Courtesy of CBC News Nova Scotia - Brendan Childerley and his family want to thank the people they say saved his life on Feb. 23.
Courtesy of BT.com - Cardiomyopathy is a condition that can affect babies, children and adults of all ages, and sometimes symptoms go unnoticed.
Courtesy of CBC News - When Darlene Fournier rushed to help a man whose heart had stopped during a recreational volleyball game earlier this month, she didn't have time to think about anything other than what to do to get the man breathing again.
WARREN, NJ – Two Watchung Hills students who helped to save a classmate's life were recognized at the meeting of the Watchung Hills Board of Education on Tuesday.
Good4Utah.com - It may be shocking to see a young, seemingly healthy child go into sudden cardiac arrest.
Courtesy of BramptonGuardian.com - In what was a remarkable seven-day stretch in Peel recently, 14 bystanders leapt into action to try to save lives using CPR and publicly available AEDs.
Courtesy of Stanford Medicine - Moderate exercise may not only be safe for patients with hypertrophic cardiomyopathy, the heart disease most commonly associated with sudden death in athletes, but could provide important health benefits as well, according to a study published in JAMA today.
The Spurs star forward had been ruled out indefinitely following a test that showed a minor case of arrhythmia over the weekend.