Magnetic properties of Cr-doped SnO2 and the effects of oxygen vacancy (VO) on the magnetic properties were examined to understand the origin of ferromagnetism in Cr-doped SnO2 and explain the observed discrepant phenomena. Cr-doped SnO2 showed a p–d hopping ferromagnetic interaction that decreases gradually with the increase in Cr–Cr distance. In Cr-doped SnO2 with VO, ferromagnetic interaction was obviously weakened. Exchange constants indicated that the ferromagnetic exchange interaction in Cr-doped SnO2 was similar to that in Co-doped SnO2, while it was similar to that in Fe-doped SnO2 and/or undoped SnO2 with tin vacancy (VSn) in the presence of VO.

Effects of Oxygen Vacancy on the Magnetic Properties of Cr-Doped SnO2: Density Functional Investigation. W.Wei, Y.Dai, M.Guo, Z.Zhang, B.Huang: Journal of Solid State Chemistry, 2010, 183[12], 3073-7