The Spin on Electronics!

Today, nearly all microelectronic devices are based on storing or flowing the electron’s charge. The electron also possesses a quantum mechanical property termed “spin”, that gives rise to magnetism. Electrical current is comprised of “spin-up” and “spin-down” electrons, which behave as largely independent spin currents. The flow of these spin currents can be controlled in thin-film structures composed of atomically thin layers of conducting magnetic materials separated by non-magnetic conducting or insulating layers. The resistance of such devices, so-called spin-valves and magnetic tunneling junctions, respectively, can be varied by controlling the relative magnetic orientation of the magnetic layers, giving rise to magnetoresistance tailored for different applications. Recent advances in generating, manipulating and detecting spin-polarized electrons and electrical current make possible new classes of spin based sensor, memory and logic devices, generally referred to as the field of spintronics. In particular, the spin-valve is a key component of all magnetic hard-disk drives manufactured today and enabled their nearly 1,000-fold increase in capacity over the past eight years1. The magnetic tunnel junction allows for a novel, high performance random access solid state memory which maintains its memory in the absence of electrical power. The respective strengths of these two major classes of digital data storage devices, namely the very low cost of disk drives and the high performance and reliability of solid state memories, may be combined in the future into a single spintronic memory-storage technology, the magnetic Racetrack. The Racetrack is a novel three dimensional technology which uses nanosecond long pulses of spin polarized current to move a series of magnetic domain walls along magnetic nanowires2.
1. Stuart Parkin et al., Magnetically engineered spintronic sensors and memory. Proc. IEEE 91, 661-680 (2003).
2. S. S. P. Parkin, US Patent # 6,834,005, 6,898,132, 6,920,062, 7,031,178, and 7,236,386 (2004-2007).