Microstructure and magnetic properties of oxidized titanium nitride thin films in situ grown by pulsed laser deposition

Different oxidation states of titanium nitride thin films, including pure TiN(h 0 0), TiN1-xOx(h 0 0), Ti2O3(0 0 l) and pure anatase TiO2(0 0 l), were prepared by pulsed laser deposition with various oxygen pressures (P-O2) using a TiN target. Elaborative evolutions of the crystal and electronic structures of the obtained films were examined systematically by x-ray diffraction and x-ray absorption spectroscopy. We found that the Ti2O3(0 0 l) film, which was prepared at oxygen pressures P-O2 = 10(-4) Torr, exhibited the maximum room temperature ferromagnetism (RTFM) behaviour. The bound magnetic polaron model is used to clarify the origin of RTFM in these films.