Electronic states of ordered and disordered thin Co/sub 2/MnSi films for spintronics applications

The authors have measured the magnetic and optical properties of single phase Co
₂
MnSi epitaxial films produced by pulsed laser deposition on gallium arsenide substrates at various temperatures. The intrinsic atomic disorder is shown to result in profound changes in the magnetic moment, Curie temperature and half metallic properties of the films. Specifically, with increased disorder, the majority carrier numbers decrease rapidly and disappear, the minority bandgap edge moves to lower values (0.18eV vs 1.8eV) and the optical conductivity shows features typical of a narrow bandgap semiconductor