Room temperature ferromagnetism in transition metal (V, Cr, Ti) doped In2O3

Abstract

Indium oxide is chosen as the host material for doping Ti, V, and Cr transition metal ions. Theoretical calculations based on density functional theory within a local spin density approximation show that V–V separation of 5.6Å is more stable with a strong ferromagnetic coupling. Our calculations clearly predict that substitution of vanadium for indium should yield ferromagnetism in In2O3. Experimentally, (In0.95TM0.05)O3 (TM=Ti,V,Cr) were prepared using sol-gel as well as solid state reaction methods. Superconducting quantum interference device magnetization measurements as a function of field and temperature clearly showed that the V and Cr doped samples are ferromagnetic with Curie temperature well above room temperature. Thin films deposited by pulsed laser ablation using these materials on sapphire substrates exhibit a preferred 222 orientation normal to the plane of the film. The magnetic moment for (In0.95V0.05)O3 film deposited in 0.1mbar oxygen pressure was estimated to be 1.7μB∕V and is comparable to the theoretical value of 2μB∕V.