Bulk synthesis and high-temperature ferromagnetism of (In1−xFex)2O3−σ with Cu co-doping

The synthesis and magnetic properties of ${\left({\mathrm{In}}_{1-x}{\mathrm{Fe}}_x\right)}_2{\mathrm{O}}_{3-\sigma }$ bulk ceramics with Cu co-doping are reported. Magnetic Fe ions are found to have high thermodynamic solubility (up to 20%) in the ${\mathrm{In}}_2{\mathrm{O}}_3$ host compound. The lattice constant decreases almost linearly as Fe doping concentration increases indicating the incorporation of Fe ions into the host lattice. The samples with high Fe concentration annealed under Ar reduced atmosphere were found to be ferromagnetic, and the Curie temperature is around $750\mathrm{K}$ . The extensive structural and magnetic studies rule out the possibility that the observed magnetism is derived from magnetic impurity phases.