Development of high-temperature ferromagnetism in SnO2 and paramagnetism in SnO by Fe doping
We report the development of room-temperature ferromagnetism in chemically synthesized powder samples of Sn 1-x FexO2 *0.005*x*0.05* and paramagnetic behavior in an identically synthesized set of Sn 1-x Fe x O. The ferromagnetic Sn 0.99 Fe 0.01 O2 showed a Curie temperature TC=850 K, which is among the highest reported for transition-metal-doped semiconductor oxides. With increasing Fe doping, the lattice parameters of SnO2 decreased and the saturation magnetization increased, suggesting a strong structure-magnetic property relationship. When the Sn 0.95 Fe 0.05 O 2 was 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 Sn 0.95 Fe 0.05 O 2samples prepared at and above 350 °C, but the ferromagnetic component decreased gradually as preparation temperature approached 600 °C. All Sn 0.95 Fe 0.05 O 2 samples 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 Fe 3+ spins observed in the Sn 0.95 Fe 0.05 O 2sample prepared at 350 °C is only *24% of the uniformly incorporated Fe 3+ . No evidence of any iron oxide impurity phases were detected in Sn 1-x FexO2or Sn 1-x Fex2 and SnO, and their oxygen stoichiometry.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 859428
- Report Number(s):
- PNNL-SA-46755; 9995; KP1704020; TRN: US200714%%44
- Journal Information:
- Virtual Journal of Nanoscale Science & Technology, 12(7), Vol. 12, Issue 7
- Country of Publication:
- United States
- Language:
- English
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