Probing interband and intraband transitions in magneto-optical FeT (T = Cr, Co, Ni) alloys from electronic structure studies

Abstract

Photoelectron spectroscopy as a function of temperature is used to study interband and intraband transitions in magneto-optical FeT (T = Cr, Co, Ni) alloys. Valence band studies on these alloys indicates a strong d-d hybridization between Fe and T atoms which gives rise to localized valence states and contributes to direct interband transition while the s-d hybridized band contribute to the intraband transition and give rise to the spin polarized conduction electrons. The analysis of core levels shows that the spin orbit coupling is influenced by the near neighbour interaction between Fe and T atoms. The exchange interaction has the temperature dependence which drives the itinerant electron magnetism in FeT alloys. We find that the large density of the itinerant states at the Fermi edge and the large separation between the localized and the itinerant electronic state in FeCr are crucial for the large magneto-optical property reported in this system. In FeCo and FeNi, the overlapped localized and itinerant electronic states make these materials optically anisotropic.