MAGNETOOPTICAL PROPERTIES OF CRO2

The magneto-optical, polar Kerr effect of polycrystalline CrO2 has been studied in the range 0.8-5 eV. The maximum Kerr rotation amounts to \theta(K)\ = 0.154-degrees at 3.7 eV. Two different interpretations of the observed magneto-optical transitions are discussed: (1) based on published spin-polarized band-structure calculations and (2) based on published spin-polarized photoemission data. Additional transport measurements are made to elucidate the free-electron contributions. At room temperature, the electrical resistivity is 190 muOMEGA cm, while Hall measurements show a carrier concentration of 0.5 e/f.u. in one-band model. Because of a small Kerr effect of \theta(K)\ < 0.1-degrees in the energy range 1.5-3 eV and a low reflectivity of less than 30%, CrO2 is not attractive for magneto-optical recording.