In Co-doped SnO2 fivefold degenerate Co-3d states split into five singlet states. The magnetic moment of Co was mainly contributed by the spin polarization of Co-dxy states. The introduction of oxygen vacancies largely increases the magnetic moment of Co. The increase of Co magnetic moment was caused by the conversion of spin–spin coupling between Co and its neighboring O atoms from antiparallel to parallel, which attributes to the hybridization and electrons transfer between oxygen vacancy impurity states and Co-3d states.

The origin for Increase of Magnetic Moment of Co in Co-Doped SnO2 with Oxygen Vacancies. H.Wang, Z.Zong, P.Li, Y.Yan: Physica Status Solidi B, 2011, 248[12], 2941–4