Imagine a data storage device the size of an atom, working at the speed of light. Imagine a microprocessor whose circuits could be changed on the fly. One minute, it would be optimized for database access, the next for transaction processing and the next for scientific number-crunching.
Finally, imagine a computer memory thousands of times denser and faster than today's memories. And nonvolatile, so it retains its contents when the power is off.
All of these and more are on computing's horizon, thanks to the exploding field of spintronics. Spintronics, from "spin transport electronics," isn't entirely new. The spintronic effect called giant magneto-resistance was introduced by IBM in 1997 in its GMR disk-read head. As a result, disk capacities have jumped by a factor of 100 in the past five years.
Electronic circuits are driven by electron flows, which have a charge that can be measured and controlled. But electrons not only flow; they also spin like tiny bar magnets. Depending on their orientation, the spins are said to be "up" or "down."
This additional variable, or "degree of freedom," means that electrons can do more things and convey more information than they do in conventional electronics. "Spin gives you an additional knob to turn," explains Stuart Wolf, a program manager at the Defense Advanced Research Projects Agency (DARPA), which is funding much of the spintronics research in the U.S.
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