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For years, society has marveled at how quickly devices, including computers, have become faster and smaller. But advancements in conventional electronics have slowed, with manufacturing problems and other obstacles blocking progress toward more efficiency.
Future improvements are in the hands of scientists like Igor Žutić, a pioneer in the field of spintronics who has received six-figure grants from the U.S. Navy and Air Force research offices and a $400,000 National Science Foundation CAREER award. Žutić, an associate professor and theoretical physicist who joined UB in 2005 as a member of the Integrated Nanostructured Systems strategic strength identified in the UB 2020 long-range strategic plan, explains the promise of spintronics by contrasting it with conventional electronics.
Modern, electronic gadgets record and read data as a blueprint of ones and zeros that are represented, in circuits, by the presence or absence of electrons. Processing information requires moving electrons, which consumes energy and produces heat.
Spintronic gadgets, in contrast, store and process data by exploiting a largely overlooked property all electrons possess—“spin,” which is responsible for magnetism. Electrons have an “up” or “down” spin, and these orientations can stand for the ones and zeros devices read. Since magnetic properties remain stable without a power source—consider how magnets hang on refrigerators without consuming energy—spin technology is yielding “green” devices, like memory chips that retain information when power is off.
“That has been one of the main drawing forces in spintronics: high-capacity memory devices,” he says. “However, my feeling is that this is just the tip of the iceberg.”
Žutić expects spin technology to yield energy-saving improvements in data processing, with devices processing information by “flipping” spin instead of shuttling electrons around. He and collaborators have described piezomagnetism, an “avalanche effect” in which flipping one electron’s spin in a nanoscale semicon-ductor would induce the spins of thousands of other electrons to flip. Žutić has also shown, with colleagues, that spin technology could lower power consumption and improve bandwidth of semiconductor lasers, which could transfer data 1,000 times more efficiently than copper wires.
One of his projects examines ways to introduce spintronic properties into silicon by creating an imbalance between numbers of “spin-up” and “spin-down” electrons in the semiconductor. This “spin injection” would enable the design of novel technologies using a common material. Japanese scientists have demonstrated that when an imbalance between “up” and “down” electrons exists, it is possible to use electrons’ spin to guide an electrical current flowing through a semiconductor—a phenomenon Žutić had predicted and coined “the spin-voltaic effect.”
As a theorist, Žutić ponders the basics of magnetism and spin. He has published, for instance, on the possibility that below a certain temperature, nonmagnetic materials may become magnetic as they are heated up—a concept he analogizes to warming water to produce ice.
The importance of such contributions might be difficult to grasp, but Žutić makes his case: Magnetism drives everything from bird migration to medical imaging, and discoveries of the kind he is making can open the way for important, new inventions.
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