August 16, 2005
By: Charlie Feigenoff
The current generation of electronic devices is built around an electron’s charge. The next generation will capitalize on electron spin—enabling astounding leaps in computing power and setting the stage for miniaturization so complete that computers will be virtually imperceptible.
One of the pioneers of this technology is University of Virginia materials scientist Stuart Wolf. As a program manager at the Defense Advanced Research Projects Agency, Wolf allocated large sums of money for the field, which he dubbed spintronics. He is currently working on a new form of spin-based memory—magnetic random-access memory (M-RAM)—that will make the dynamic random-access memory and hard drives found in today’s computers obsolete.
If there had been any doubts about the vast potential of spintronics, they were swept away in the late 1990s by the first device to incorporate this new technology—the giant magnetoresistance heads now used in hard drives. Because they can detect much tinier bits than older equipment, the heads have stimulated massive expansion in storage capacity and shrinkage in drive size. Without spintronics, for instance, there would be no iPods.
M-RAM promises similar advances. It’s nonvolatile , like the flash memory found in key drives and secure digital cards, but with a big difference. It is many orders of magnitude faster to write. It requires a fraction of the power. And it can be read and written to indefinitely (flash memory, in contrast, is limited to 100,000 uses). Scientists ultimately envision a single M-RAM chip providing both logic and storage for a miniaturized computer.
Wolf is investigating thin-film materials that can be combined to control the spin in an M-RAM chip by producing electronic fields, which are much easier to manage than magnetic ones. The technology used to create this complex sandwich of magnets and insulators is the same as that used to create silicon-based CMOS circuits—and highlights another critical advantage of spintronics. “Because it is compatible with existing electronics,” Wolf notes, “M-RAM provides a pathway for the future as devices enter the nanoscale.”
Wolf holds degrees from Columbia College and Rutgers University and is on the faculty of the U.Va. School of Engineering and Applied Science Department of Materials Science and Engineering. Before coming to U.Va., he spent 31 years at the Naval Research Laboratory, both as a scientist and a scientific manager. For the past 12 years , he has been program manager at DARPA, supervising projects such as s pintronics, frequency agile materials for electronics (FAME), quantum information science and technology (QuIST), advanced thermoelectrics, advanced magnets for power systems (AMPS) and, finally, superconducting hybrid power electronics (SuperHyPE).
H is primary research interest at U.Va. is in the study of spin-dependent phenomenon in thin films and alternating multilayers of magnetic and nonmagnetic metals, semiconductors and insulators. He is also interested in the use of the spin degree of freedom as a quantum bit (or qubit) for quantum information processing and in novel superconducting materials, including a host of copper oxide- and ruthenium oxide-based materials.
Wolf is a Fellow of the American Physical Society and has received many awards, including the NRL Meritorious Civilian Service Award, Sigma Xi Pure Science Award and the E. O. Hulbert Award.
