Magnetic semiconducting anatase TiO2−δ grown on (1 0 0) LaAlO3 having magnetic order up to 880 K

We demonstrate a semiconducting material, TiO2−δ, with magnetism up to 880 K, without the introduction of magnetic ions. The magnetism in these films stems from the controlled introduction of anion defects from both the film-substrate interface as well as processing under a deficient oxygen atmosphere. First-principle band structure calculations indicate that the exchange between Ti cations mediated by an oxygen anion is positive, i.e., ferromagnetic, whereas the exchange between cations via a vacancy is negative, i.e., ferrimagnetic. It is likely that both the mechanisms are active in this system. This represents a new and promising approach in the search for room-temperature magnetic semiconductors.