Observation of intrinsic half-metallic behavior of cro₂ (100) epitaxial films by bulk-sensitive spin-resolved pes

We have investigated the electronic states and spin polarization of half-metallic ferromagnet CrO₂ (100) epitaxial films by bulk-sensitive spin-resolved photoemission spectroscopy with a focus on non-quasiparticle (NQP) states derived from electron-magnon interactions. We found that the averaged values of the spin polarization are approximately 100% and 40% at 40 K and 300 K, respectively. This is consistent with the previously reported result [H. Fujiwara et al., Appl. Phys. Lett. 106, 202404 (2015).]. At 100 K, peculiar spin depolarization was observed at the Fermi level (E_F), which is supported by theoretical calculations predicting NQP states. This suggests the possible appearance of NQP states in CrO₂. We also compare the temperature dependence of our spin polarizations with that of the magnetization.