Hard disk drives (HDDs) are widely used for high-density information storage. HDDs are commonly found in computer systems traditionally associated with this type of storage, such as servers and desktop computers. However, HDDs having smaller form factors, such as one-inch drives, can also be found in hand-held electronic devices, such as music players and digital cameras.
Higher storage capacity in HDDs can be achieved by increasing storage density. This involves reducing the size of bit cells in recording media. By reducing the size of the bit cell to less than about 20 nm×20 nm, storage densities greater than one terabits per inch (1 Tb/in2) can be achieved.
However, existing read elements in read/write heads for a hard disk drive which are based on the giant magnetoresistance (GMR) effect are expected to encounter problems as they are scaled down to these sizes due to for example, spin torque and thermally-induced magnetic noise.
Alternative read elements have been suggested and much attention is being focused on devices based on the extraordinary magnetoresistance (EMR) effect.
“Quantum steering of electron wave function in an InAs Y-branch switch” by G. M. Jones et al., Applied Physics Letters, volume 86, page 073117 (2005) describes a Y-channel transistor. However, Y-channel transistors have only been considered for use as fast digital switches, for example, in information processing.