Magnetooptical Spectra in PtMnsb between 1.2 and 5.9 ev

Magnetooptical Kerr rotation and Kerr ellipticity were measured on the (111) surface of a single crystal of PtMnSb for photon energies between 1.2 and 5.9 eV. Peak Kerr rotation reaches as large as 120 min of arc in an annealed sample. Real and imaginary parts of off-diagonal conductivity tensor were calculated from the measured spectra. The obtained spectra showed a good agreement with those of polycrystalline bulk samples. The spectrum of imaginary part of off-diagonal conductivity consists of two peaks with opposite signs at 2.5 eV and 5.2 eV, the first peak being resolved into two structures in the annealed crystal. These structures are correlated with band structures.