Magneto-optical Kerr effect in Eu1−xCaxB6

Abstract

We have measured the magneto-optical Kerr rotation of ferromagnetic Eu1−xCaxB6 with x = 0.2 and 0.4, as well as of ybB6 serving as the nonmagnetic reference material. As previously for EuB6, we could identify a feature at 1 eV in the Kerr response which is related with electronic transitions involving the localized 4f electron states. The absence of this feature in the data for YbB6 confirms the relevance of the partially occupied 4f states in shaping the magneto-optical features of Eu-based hexaborides. Disorder by Ca-doping broadens the itinerant charge carrier contribution to the magneto-optical spectra. © 2004 The American Physical Society.