Anisotropic magneto-optical Kerr effect of hcp and fcc Co from first principles.

Abstract

The magneto-optical Kerr effect is investigated from first principles, using density-functional theory in the local-density approximation, for two different magnetization orientations of both the fcc and hcp phase of Co. For the fcc phase a negligible anisotropy is found in the Kerr spectra of the (100) and (110) magnetization directions. For the hcp phase the polar Kerr effect is calculated for the (0001) and the (112\ifmmode\bar\else\textasciimacron\fi{}0) magnetization directions, and a distinct anisotropy in the Kerr spectra of these two orientations is found, which agrees with experimental spectra. The origin of the anisotropy effect is analyzed, and it is concluded that over a broad energy range this magnetic anisotropy effect in hcp Co can qualitatively be described by the first-principles band-structure theory, although the d-band width of Co is overestimated by the local-density approximation.