Tunable room temperature ferromagnetism in Sn0.93Fe0.05M0.02O2−σ (M = Sb/Mg): The role of electron- and hole-doping

Bulk polycrystalline Sn0.95Fe0.05O2−σ and Sn0.93Fe0.05M0.02O2−σ (M = Sb/Mg) samples were fabricated. Detailed X-ray diffraction and transmission electron microscopy analyses revealed that the dopants most probably replaced the Sn in SnO2 structure, instead of forming impurity phase or nanocluster. By varying the dopant M (Sb/Mg), the electron- (Sb) and hole- (Mg) doping effect on the magnetic properties of Sn0.93Fe0.05M0.02O2−σ was investigated. Compared with Sn0.95Fe0.05O2−σ, the saturation magnetization decreased after doping with Sb and increased after doping with Mg. The changes of Fe oxidation state and carrier type, discovered from X-ray photoelectron spectroscopy, are believed to be responsible for the co-doping tuned ferromagnetism in Sn0.93Fe0.05M0.02O2−σ.

► We reported a carrier doping tuned ferromagnetism in SnO2: Fe.
► n-type doping (Sb-doping) decreased the saturation magnetization of SnO2: Fe.
► p-type doping (Mg-doping) increased the saturation magnetization of SnO2: Fe.
► An oxidation state transition of Fe in different doping case (Sb/Mg) was observed in XPS.
► We attributed the oxidation state transition of Fe to the doping tuned ferromagnetism.