Ferromagnetic semiconductors and the role of disorder – Bruce Wessels

Date: Mon. December 6th, 2010, 12:30 pm-1:30 pm
Location: Rockefeller 221

Magnetic semiconductors having Curie temperature greater than 300 K are of interest for a wide variety of spintronic device applications. Short-range order has been reported to stabilize ferromagnetism in transition metal-doped III-V compound semiconductors. While both theory and experiment have centered on dilute magnetic semiconductors where the magnetic ions substitute randomly for cation sites, there is increasing evidence that correlated substitution needs to be considered. Evidence of correlated substitution comes from structural analysis (extended x-ray absorption fine structure (EXAFS)), magnetic property and recent magneto-optical property measurements as well as theory. Furthermore, there is growing theoretical and experimental support that ferromagnetic semiconductors with Curie temperatures well above room temperature can be formed through correlated substitution. Future materials research will be well served by identification and examination of semiconductor systems that favor short-range ordering of magnetic constituents.