Electronic structure of half-metallic CrO2 as investigated by optical spectroscopy

Temperature variation of absorption spectra has been investigated for ferromagnetic CrO2 films (T-C = 390 K) in the temperature range of 8 - 450 K. We have observed temperature-sensitive absorption components at approximate to 0.5 eV, approximate to 1.0 eV, and approximate to 1.5 eV, whose spectral weights scale well to (M/M-s)(2). These observations suggest that CrO2 has a characteristic electronic structure with local spins and exhange-split bands and can be viewed as a double exchange system.