Room-temperature observation of high-spin polarization of epitaxial CrO2(100) island films at the Fermi energy

Abstract

Epitaxial CrO2(100) island films have been grown on TiO2(100) substrates by a chemical-vapor deposition technique. Well-controlled surface and interface properties of the CrO2(100) films were confirmed by scanning tunneling microscopy and transmission electron microscopy, respectively. Spin- and angle-resolved photoemission spectroscopy at room temperature revealed an energy gap of about 2 eV below Fermi level EF for spin-down electrons and a spin polarization of about +95% at EF. After extended sputtering, the spin polarization can be recovered from about +10% up to +85% upon annealing.