Room-Temperature d⁰ Ferromagnetism in Nitrogen-Doped In₂O₃ Films

N-doped In₂O₃ films were deposited on fused quartz substrates by radio-frequency magnetron sputtering with different N₂ flux. X-ray diffraction patterns, x-ray photoelectron spectroscopy and the optical transmittance spectra indicate that nitrogen has incorporated into the In₂O₃ lattice. Room-temperature d⁰ ferromagnetism is observed in all the films. The saturation magnetization increases from 0.73 to 3.5 emu/cm³ when the N₂ flux varies from 0 to 10 sccm. The concordant results in structural, compositional, optical and magnetic properties suggest that this d⁰ ferromagnetism is associated with the N incorporation and may be mediated by the long-range p–p interaction between the N 2p states.