Low-temperature Kerr spectroscopy on half-metallic Sr2FeMoO6

The polar Kerr rotation and ellipticity spectra of epitaxially grown (001)- oriented half-metallic Sr2FeMoO6 thin films have been determined in the pho ton energy range from 1.2 to 4.9 eV. The Kerr rotation spectrum shows three maxima at E=1.6, 4.0, and 4.65 eV. The maxima at 4.0 and 4.65 eV are consi stent with spin-polarized band structure calculations for interband transit ions from the O-2p to the minority-spin pi*Mo/Fe and majority-spin Mo-t(2g) bands, respectively. The overall maximum intrinsic Kerr rotation is Theta( K)=-0.045 degrees at a photon energy of 4.65 eV. The maximum of Theta(K) at E=1.6 eV coincides with a minimum in the reflectivity due to the plasma ed ge of Sr2FeMoO6 and, therefore, is not related to an interband transition. (C) 2000 American Institute of Physics. [S0003-6951(00)00640-9].