Based on hybrid density-functional calculations, we propose that ferromagnetism in the prototypical bixbyite sesquioxide ${\text{In}}_2$${\text{O}}_3$ doped with Cr is due to Cr-oxygen vacancy complexes, while isolated Cr cannot support carrier-mediated magnetic coupling. Our proposal is consistent with experimental facts such as the onset of ferromagnetism in O-lean conditions only, the low or vanishing net moment in unintentionally doped material, and its increase upon intentional doping.

• Received 13 December 2013
• Revised 8 April 2014

DOI:https://doi.org/10.1103/PhysRevB.89.134423