High temperature ferromagnetism in Ni-doped In2O3 and indium-tin oxide

Observation of high temperature ferromagnetism in Ni-doped In2O3 and indium-tin-oxide (ITO) samples prepared by a solid state synthesis route is reported. Both Ni-doped compounds showed a clear ferromagnetism above 300 K with the magnetic moments of 0.03–0.06µB/Ni and 0.1µB/Ni at 300 and 10 K, respectively. Ni-doped In2O3 samples showed a typical semiconducting behavior with a room temperature resistivity of ρ ~ 2 Ω cm, while Ni-doped ITO samples were metallic with ρ ~2×10–2 Ω cm. Analysis of different conduction mechanisms suggested that variable range hopping model explains our ρ -T data for the Ni-doped In2O3 sample the best.