April 7 , 2008
3pm in Howey Physics Lecture Room 5

 

Kenneth Burch
Center for Integrated Nanotechnologies
Los Alamos National Laboratory

 

"Optical Investigation and Manipulation of Spintronics Materials"

 

The field of spintronics aims to deliver novel multi-functional devices by manipulating magnetism on unprecedented length and time scales. Furthermore spintronic materials provide a unique opportunity to study carrier mediated magnetism in a well controlled environment. We first focus on the important role optical studies have played in our understanding of the electronic structure of III-Mn-V ferromagnetic semiconductors. These extensive studies have established the electronic structure is strongly affected by the strength of the exchange between the Mn local moments and the holes they introduce. Particular focus is given to GaMnAs, where spectroscopic studies suggest strong correlations play a role in the metallic state. Finally, we will detail our recent experiments into the ultrafast manipulation of magnetism on the nanoscale in MnAs. Our results also suggest the electronic structure plays a key role in the first order phase transition.