Structural and magnetic–luminescent properties of carbon-doped aluminum oxide

Abstract

Three-phase (corundum + δ phase + amorphous phase) amorphous–nanocrystalline powders of pure and carbon-doped Al₂O₃ (x_C = 1.07–6.6 wt %) have been produced by pulsed electron beam evaporation in vacuum. The corundum hexagonal nanocrystals in the Al₂O₃–C nanopowder (x_C = 1.07 wt %) had sizes about 5 nm. The carbon solubility boundary in the Al₂O₃ lattice was lower than 1.07 wt % C. The dependence of the form of the cathode-luminescence spectra and the phase compositions of the prepared Al₂O₃ and Al₂O₃–C nanopowders has been found. The absence of R lines of Cr³⁺ ions in photoluminescence spectra of doped nonopowders has been detected. All the nanopowders of the pure and C-doped Al₂O₃ were ferromagnets at room temperature with the maximum magnetization of ~0.12 emu/g at x_C = 6.6 wt %.