Journal of Powder Materials (한국분말재료학회지)

The Korean Powder Metallurgy & Materials Institute (한국분말재료학회 (*구 분말야금학회))
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Room-temperature Ferromagnetism in Fe-doped Reduced TiO2-δ

산소 결핍에 따른 Fe가 도핑된 TiO2-δ의 상온 강자성 현상에 관한 연구

  • Lee, H.M. (Nuclear Nanomaterials Development Lab., Korea Atomic Energy Research Institute) ;
  • Kim, C.S. (Department of Physics, Kookmin University) ;
  • Uhm, Y.R. (Nuclear Nanomaterials Development Lab., Korea Atomic Energy Research Institute) ;
  • Rhee, C.K. (Nuclear Nanomaterials Development Lab., Korea Atomic Energy Research Institute)
  • 이희민 (한국원자력연구소 원자력나노소재응용랩) ;
  • 김철성 (국민대학교 물리학과) ;
  • 엄영랑 (한국원자력연구소 원자력나노소재응용랩) ;
  • 이창규 (한국원자력연구소 원자력나노소재응용랩)
  • Published : 2006.12.28
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Abstract

Effects of oxygen deficiency on the room temperature ferromagnetism in Fe-doped reduced $TiO_2$ have been investigated by comparing the air-annealed $Ti_{0.97}Fe_{0.03}O_2$ compound with secondly post-annealed one in vacuum ambience. The air-annealed sample showed a paramagnetic behavior at room temperature. However, when the sample was further annealed in vacuum, a strongly enhanced ferromagnetic behavior was observed at same temperature. $M{\"{o}}ssbauer$ spectra of air-annealed sample at 295K showed a single doublet of $Fe^{3+}$, suggesting that the Fe ions are paramagnetic. On the other hand, the absorption spectra after vacuum-annealing exhibited two doublets, in which one is the same component with air-annealed sample and the other is new doublet corresponding to $Fe^{2+}$ state. This result suggests that the occurrence of ferromagnetism in reduced sample may be interpreted as the contribution of unquenched orbital moment of $Fe^{2+}$ ions.

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