Calculated magneto-optical properties of cubic and tetragonal Fe, Co, and Ni

Recent experiments suggest that the linear magneto-optical signal from thin surfaces differs significantly from the corresponding bulk signal. Using an ab initio full potential linear muffin-tin orbital method, we have therefore calculated the polar magneto-optical Kerr signal for tetragonal and cubic Fe, Co, and Ni, in order to elucidate the role of tetragonal distortion on magneto-optical spectra. Our calculations indicate that for all three metals, the amplitudes and positions of the peaks in the Kerr spectra do change due to the tetragonal distortion, but the effect is not dramatic, and far from the observed differences. We therefore conclude that the large observed differences must have another origin, and discuss possible sources. Furthermore, since magneto-optical spectra are very sensitive to details in the wave functions and density, calculation of such spectra constitutes an important test of any ab initio method. The highly accurate method used in the present calculations differs from previously used methods in several respects, and a comparison between the different methods is made.