Anisotropy of orbital moments and magnetic dipole term Tz in CrO2. An ab initio study

Abstract

A systematic study is performed by the ab initio density-functional theory of the anisotropy of the orbital moments (lz) and the magnetic dipole term (Tz) in bulk CrO2. Two different band-structure techniques are used (full potential linearized-augmented-plane-wave method and linear-muffin-tin-orbital method in the atomic-sphere approximation), and the electronic correlations are treated by the local-spin-density approximation (LSDA), the LSDA + orbital polarization method, and the LSDA + U method. The calculated anisotropies of (lz) and (Tz) are very large compared to Fe, Ni, and Co but still a factor of 5 and 2 smaller than the anisotropies obtained from a recently suggested analysis of the x-ray magnetic circular dichroism spectra for a thick layer of CrO2.