Infrared probe of the electronic structure and carrier scattering in NiMnSb thin films

We report the use of infrared reflectance spectroscopy to examine the electronic structure of epitaxial, sputter deposited thin films of the predicted half-metallic ferromagnet NiMnSb. The contribution of the interband transitions to the optical conductivity, as well as the spectral weight of conducting carriers, agree with the band structure calculations predicting a half-metallic state in NiMnSb. The intraband response of conducting carriers is different from that of a Drude metal and is consistent with a partial gap in the minority-spin density of states.