Electronic structure and magnetic properties of sub-3 nm diameter Mn-doped SnO2 nanocrystals and nanowires

Abstract

Manganese-doped SnO2 nanocrystals and nanowires with diameters below SnO2 Bohr radius were synthesized by solution methods. X-ray absorption studies reveal that dopant ions are substitutionally incorporated as Mn2+ and Mn3+. Mn2+ is the dominant species at low doping levels, but the fraction of Mn3+ increases with doping concentration. Room-temperature ferromagnetism with the saturation moment of 0.27 μB/Mn is observed for nanocrystalline films containing high fraction of Mn2+ dopant, which is associated with hybridization of Mn2+ d-levels with a donor-impurity band. These results imply the possibility of manipulating magnetic interactions via dopant electronic structure and quantum confinement of the host lattice.