Room temperature ferromagnetism in Cr-doped In2O3 on high vacuum annealing of thin films and bulk samples

We report on the observation of room temperature ferromagnetism in Cr-doped In2O3 bulk samples and spin-coated thin films. The samples showed a clear ferromagnetism above 300 K with magnetic moments of 0.008 and 0.22 mu(B)/Cr at 300 K for the bulk and thin film, respectively, only after high vacuum (HV) annealing at 600 degrees C. The vacuum annealed Cr-doped In2O3 thin films showed a typical semiconducting behavior with a room temperature resistivity of 0.73 Omega cm, while bulk samples were more conducting (23 m Omega cm). We present systematic investigations on the influence of HV annealing on the carrier concentrations, resistivity, and magnetic properties of the samples. (c) 2007 American Institute of Physics.