A collaboration of researchers has flipped micron-sized magnets
as quickly as their fundamental speed limit will allow. In two
papers published in the 10 January print issue of PRL, the
researchers describe applying an ultrafast magnetic field pulse
to reverse micromagnets almost as fast as the switching of a bit
on a Pentium chip. But unlike silicon circuitry, a magnetic
switch preserves data without the need for a constant power
supply. The work strengthens hopes that fast and efficient
magnetic memory could soon replace technology used in mobile
phones and digital cameras. Storage media such as hard drives
and digital tape represent the ones and zeros of data using the
orientations of tiny bar magnets: “up” for one value and “down”
for the other. The bar magnets are “domains,” each containing
many atoms whose net magnetic alignment is called the
magnetization of the region. To be useful for memory–rather than
longer-term storage–a device must switch between states quickly,
efficiently, and reliably. Today’