Comparison of the mid-Infrared magneto-optical response of Ga _1-x Mn _x As films grown by molecular beam epitaxy and ion implantation and pulsed laser melting

We have carried out mid-infrared magneto-optical studies of Ga _1-x Mn _x As films grown using two different techniques: low temperature molecular beam epitaxy (LT-MBE) and a combination of ion-implantation and pulsed laser melting (II-PLM). The second method is a high temperature growth technique which minimizes the formation of Mn interstitials. Both samples exhibit a ferromagnetic response with similar Curie temperatures (T _C). The samples show qualitatively similar behavior in below bandgap Faraday and Kerr measurements, which probe the valence band structure of the materials. This suggests that the same mid-infrared transitions are dominating the magneto-optical response of both samples.