Magneto-optical spectra of bismuth-substituted gadolinium iron garnets in vacuum ultraviolet

Abstract

Magneto-circular dichroism and Kerr rotation spectra in bismuth-substituted gadolinium iron garnets with various bismuth concentrations were measured at 320 K in the photon energy range between 15 and 40 eV. The spectra show six fine structures with bismuth concentration dependence. Spectra of the imaginary part of dielectric constant, which are obtained from normal reflectivity spectra, are decomposed into the spectrum associated with Gd 3+ ions and that associated with Bi 3+ ions. From a comparison with the decomposed spectra, three structures in the magneto-circular dichroism and Kerr rotation spectra are assigned to the transitions of Bi 3+, and other three structures to the transitions of Gd 3+.