Revolutionary Chameleon Magnets

Igor Zutic, a researcher at UB, has been pondering the usefulness of magnets and how they could transform the world of computing. He believes that magnets could aid with high capacity and low energy memory, data storage and data transfer devices.

In the most recent issue of Science, Zutic and UB physicist John Cerne talked about Japanese scientists who demonstrated a materials ability to turn its magnetism on and off at room temperature. All materials have electrons and those electrons have something called "spin". The spin can be either up or down and when the electrons within the material have the same spin it becomes magnetic. The Japanese added cobalt to titanium dioxide which is a nonmagnetic semiconductor. This created a new material that can go from nonmagnetic to magnetic at room temperature similar to the characteristics of a chameleon.

Zutic was fascinated by this discovery and believed it could be revolutionary to "spintronics". The "spin" of these electrons could be exploited to make spintronic gadgets more useful.

The chameleon magnets could "help us make more versatile transistors and bring us closer to the seamless integration of memory and logic by providing smart hardware that can be dynamically reprogrammed for optimal performance of a specific task," according to Zutic and Cerne.

"Large applied magnetic fields can enforce the spin alignment in semiconductor transistors," they said. "With chameleon magnets, such alignment would be tunable and would require no magnetic field and could revolutionize the role ferromagnets play in technology."

Zutic stated in an interview that by sending an electric voltage into a semiconductor that has been injected with cobalt or other magnetic impurities could create another chameleon magnet. Heat and light could also have the same effect on electrons which would then free them - providing information about spins and their alignment.

This idea to create heat-based chameleon magnets has eluded Zutic thus far because many scientists believe that magnetic materials would lose their neat alignments when heated. However, heating a material introduces additional carriers that can make electrons have the same spin and would actually cause them to become magnetic.

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Image: Spintronics device. Credit: Jon Cox, University of Delaware