Ultraviolet Magneto-Optical Properties of Single-Crystal Ferrimagnetic Ferric Oxide Compounds

Abstract

The first uv measurements of the complex polar‐Kerr effect (rotation and ellipticity) are reported between 1.7 and 5.64 eV for representative ferrimagnetic ferric oxide compounds containing both octahedral (Fe_oct) and tetrahedral (Fe_tet) sites. Room‐temperature measurements on bulk single crystals of pure and Ga‐doped rare earth iron garnets, spinel ferrites, and magnetoplumbite are used to distinguish between the contributions of Fe_oct and Fe_tet to the magneto‐optical spectra. Analysis shows that charge‐transfer transitions at about 4 and 5 eV, associated with Fe_oct and Fe_tet, respectively, are responsible for the principal uv magneto‐optical spectra of all the compounds studied. A model based on anisotropic orbital quenching explains why magneto‐optical effects in the orthoferrites are of the same order of magnitude as those in the ferrimagnetic ferric oxide compounds, even though the net magnetizations of the latter are typically an order of magnitude larger.