120 Physics Building
Prof. Ian Ferguson, Missouri Science and Technology - Rolla, presents, "Are the Dilute Magnetic III-Nitrides a Route to Room Temperature Spintronics?" Dr. Ferguson's presentation begins at 4 p.m. on Monday, April 10 in Room 120 Physics Building. Refreshments will be served at 3:30 p.m. in Room 223A.
In this presentation, the current theoretical and experimental status of transition metal and rare earth doped III-Nitrides are discussed and their suitability for room temperature spintronic applications is reviewed. Reports of room temperature ferromagnetism in these materials are complicated by disparate crystalline quality and phase purity, as well as conflicting theoretical predictions as to the nature of ferromagnetic behavior. For example, it is still not well understood whether the ferromagnetism derives from an intrinsic material property or from nano-scaled cluster distributions in the system. In addition, when ferromagnetism is observed it is not clear if it is free carrier mediated as there have only been a few reports of Anomalous Hall Effect and Circular Magnetic Dichroism measurements. In this work, III-Nitride materials and quantum structures have been grown by metal organic chemical vapor deposition doped with Mn, Fe, Cr and Gd. The predominant theoretical models and predictions for ferromagnetism in the III-Nitrides are compared with the available literature. In particular, the correlation of the structural, optical, and magnetic behavior in Dilute Magnetic III-Nitride Semiconductors are analyzed and compared to materials produced by other growth techniques. A complete understanding of these materials, and ultimately intelligent design of room temperature spintronic devices, will require an exploration of the relationship between the processing techniques, resulting transition metal or rare earth atom configuration, defects, electronic compensation and other physical properties coupled to accurate theory.