Room temperature ferromagnetism in Mn-doped γ-Ga2O3 with spinel structure

Mn-doped Ga2O3 (7 cation % of Mn) thin film has been grown on c-cut sapphire substrate using pulsed-laser deposition technique. Electron diffraction analyses by transmission electron microscopy found that the Mn-doped film shows γ phase with spinel structure, which is different from undoped film showing β phase. No secondary phase can be detected. Combination of Mn-L2,3 near edge x-ray absorption experiments with first-principles many-electron calculations unambiguously implies that Mn atoms are located at tetrahedrally coordinated Ga sites with a valence of +2. The doped sample shows ferromagnetism up to 350K.