Magnetoelectronics and Spintronics
SpinAps (IBM-Stanford Spintronic Science and Applications Center) - overview
The word “spintronics” (short for “spin electronics”) refers to devices that take advantage of electrons' quantum property called “spin.” Electrons don't actually spin around an axis, although in many ways they may behave as if they do. More familiar is the electron's quantum property of “negative charge”: Moving charge creates electrical current.
The IBM-Stanford Spintronic Science and Applications Center (SpinAps)
SpinAps was established in 2004 to foster a unique understanding of and experimental capabilities in magnetism and magnetic materials, combining the experience and expertise in metal-insulator heterostructures at the IBM Research - Almaden with the theoretical and experimental work in semiconductors at Stanford University. This dynamic collaboration between Almaden scientists and engineers, Stanford faculty, and students and post-doctoral fellows working at both facilities aims to both elucidate the theoretical and practical fundamentals of the emergent field of spintronics and develop disruptive advanced technology built on those fundamentals.
More about spintronics
Electron spin has two possible states, either “up” or “down.” Aligning spins in a material creates magnetism. Moreover, magnetic fields affect the passage of “up” and “down” electrons differently. Under normal conditions, the spins of conducting electrons are roughly half-up and half-down. Controlling the spin of electrons within a device can produce surprising and substantial changes in its properties. A new generation of devices based upon the manipulation of spins in solids may have entirely new functionality that could provide a foundation for entirely new computational paradigms.
For example, the first widely used spintronic device -- the Giant Magnetoresistive (GMR) spin-valve head for magnetic hard-disk drives -- exhibits large changes in electrical resistance due to variations in the relative magnetic orientation of layers on either side of a spacer layer only 2-3 atoms thick. When the orientations are in the same direction (“parallel”), electrons with one type of spin pass freely while those with the opposite spin meet greater resistance. When the magnetic orientations are in opposite directions (“antiparallel”), all the electrons meet resistance, resulting in a high overall electrical resistance through the head. By designing the structure so a faint external magnetic field would change the relative magnetic orientations of the key layers, the GMR head became an extraordinarily sensitive magnetic-field sensor. Pioneered by IBM in 1997, the GMR head enabled hard-disk drives to read smaller data bits, which led to a more than 40-fold increase in data-storage density over the past seven years.
Spintronic structures are also at the heart of Magnetic Random Access Memory (MRAM), a fast non-volatile memory concept originally proposed by IBM and currently being developed by IBM, Infineon and others, and the Racetrack Memory Project, a new storage-class memory technology.