Magneto-optical properties ofCrO2

The magneto-optical, polar Kerr effect of polycrystalline ${\mathrm{CrO}}_2$ has been studied in the range 0.8–5 eV. The maximum Kerr rotation amounts to ‖${\mathrm{\theta }}_{\mathit{K}}$‖=0.154° 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 μΩ cm, while Hall measurements show a carrier concentration of 0.5 e/f.u. in a one-band model. Because of a small Kerr effect of ‖${\mathrm{\theta }}_{\mathit{K}}$‖<0.1° in the energy range 1.5–3 eV and a low reflectivity of less than 30%, ${\mathrm{CrO}}_2$ is not attractive for magneto-optical recording.