<i>d</i> carrier induced intrinsic room temperature ferromagnetism in Nb:TiO2 film

Abstract

High crystalline anatase TiO2 and Nb:TiO2 thin films were fabricated on LaAlO3 (100) substrates by pulsed laser deposition. Room temperature ferromagnetism was obtained in Nb:TiO2 but absent in pure TiO2. The Kondo effect and anomalous Hall effect observed in metallic Nb:TiO2 strongly confirmed the existence of exchange interaction between intrinsic local magnetic moments and carriers. High energy resolution x-ray photoelectron spectroscopy studies of the Nb:TiO2 thin film revealed clear signals of Ti3+ and Nb4+ ions, which had one unpaired d electron responsible for the local magnetic moments. This result consisted quite well with the spin polarized first principle calculation.