We report the development of room-temperature ferromagnetism in chemically synthesized powder samples of Sn1-xFexO 2(0.005≤x≤0.05) and paramagnetic behavior in an identically synthesized set of Sn1-xFexO. The ferromagnetic Sn 0.99Fe0.01O2showed a Curie temperature T C=850 K, which is among the highest reported for transition-metal- doped semiconductor oxides. With increasing Fe doping, the lattice parameters of Sn O2decreased and the saturation magnetization increased, suggesting a strong structure-magnetic property relationship. When the Sn 0.95Fe0.05O2was prepared at different temperatures between 200 and 900 C, systematic changes in the magnetic properties were observed. Combined Mössbauer spectroscopy and magnetometry measurements showed a ferromagnetic behavior in Sn0.95Fe 0.05O2samples prepared at and above 350 C, but the ferromagnetic component decreased gradually as preparation temperature approached 600 C. All Sn0.95Fe0.05O2samples prepared above 600 C were paramagnetic. X-ray photoelectron spectroscopy, magnetometry, and particle induced x-ray emission studies showed that the Fe dopants diffuse towards the surface of the particles in samples prepared at higher temperatures, gradually destroying the ferromagnetism. Mössbauer studies showed that the magnetically ordered Fe3+spins observed in the Sn0.95Fe0.05O2sample prepared at 350 C is only ∼24% of the uniformly incorporated Fe3+. No evidence of any iron oxide impurity phases were detected in Sn1-xFexO 2or Sn1-xFexO, suggesting that the emerging magnetic interactions in these systems are most likely related to the properties of the host systems Sn O2and SnO, and their oxygen stoichiometry.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 1 Dec 2005|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics