Magnetic, optical, and magneto-optical properties of MnX (X=As, Sb, or Bi)from full-potential calculations

The magneto-optic (MO) Kerr and Faraday spectra for manganese pnictides are calculated using the all electron, relativistic, full-potential linear muf fin-tin orbital method. The amplitude of our calculated spectra are found t o be in good agreement with corresponding experimental spectra. Although th e MO property is a rather complicated function of the diagonal and off-diag onal elements of the optical conductivity tenor, present theory nevertheles s provides very practical insight about its origin in these compounds. The largest Kerr effect observed in MnBi can be understood as a combined effect of maximal exchange splitting of Mn 3d states and the nearly maximal spin- orbit (s-o) coupling of Bi. The frequency-dependent optical properties, nam ely reflectivity, absorption coefficient, electron-energy-loss spectra, ref ractive index, extinction coefficient are given. From our calculations (inc luding spin-orbit coupling and orbital polarization) the site-projected spi n and orbital moments are also obtained and compared to the available exper imental values and a good agreement is found. The magnetic anisotropy energ y is calculated with a minimal number of approximations for the three syste ms. A disagreement between theory and experiment is found. Using the genera lized gradient corrected full-potential Linear augmented plane-wave method we have calculated the unscreened plasma frequencies and the hyperfine para meters such as electric-field gradient as well as the hyperfine field. [S01 63-1829(99)01419-8].