Tuesday, June 13, 2006

"CHIPS: Indium oxide may best GaAs for spintronics"

Harnessing electron spin for optomagneto-electronic devices will depend on materials that, like silicon, can separately adjust their densities and dopant levels to designer specifications. Indium oxide doped with chromium may fill the bill, according to a research team from the Massachusetts Institute of Technology and Boise State University. Lacking the limitations of gallium arsenide-based ferromagnetic materials, chromium-doped indium oxide could enable durable, transparent thin-film spintronic devices, said researchers at MIT's Francis Bitter Magnet Lab. According to the researchers, ferromagnetic memories will need to harness spintronic approaches within a decade as they scale down into molecular-sized magnetic domains to store information. Chromium-doped indium oxide and similar formulations could enable the magnetic spin of even individual molecules to be flipped from "up" to "down," potentially packing a bit of data into every atom. By the time FRAMs scale down to molecular-sized domains, MIT researchers hope to have chromium-doped indium oxides fully characterized and ready to build spintronic devices. For now, they are merely reporting that they have overcome the basic limitations of other ferromagnetic formulations, especially those using GaAs, by adjusting the location of molecules in the crystalline lattice of indium oxide and by setting the dopant levels separately.