Effects of degeneracy removal on optical and magneto-optical properties of 3d ferromagnetic metals

The authors consider the effects of degeneracy removal due to magnetism and spin-orbit coupling on the optical and magneto-optical properties of Fe, Co and Ni. Both analytical and numerical calculations were carried out in order to investigate the frequency dependence of the conductivity tensor in the presence of spin-polarisation and spin-orbit coupling. Anomalies of the tensor are predicted in the infrared region at energies of the order of the spin-orbit splitting. A universal explanation is proposed for these anomalies. This is that paired singularities of the tensor components, at energies of the order of the d-band give information about the exchange splitting of the d-band. The obtained results are in accordance with optical, magneto-optical and photoemission measurements.