산소 결핍된 TiO₂-δ 박막의 철 도핑에 의한 전기적, 자기적 특성 변화

다국어 초록 (Multilingual Abstract)

Oxygen-deficient anatase and rutile titanium dioxide (TiO₂-δ) thin films were prepared by a sol-gel method and their structural, electronic, and magnetic properties were investigated. Both anatase and rutile TiO₂-δ : Fe films exhibited ferromagnetism at room temperature for a limited range of Fe doping. For the same amount of Fe doping, the anatase sample exhibited a higher magnetic moment than the rutile one. Result of conversion electron Mossbauer spectroscopy measurements indicates that Fe³+ ions substituting the octahedral Ti⁴+ sites mainly contribute to the room-temperature ferromagnetism. Some of the anatase TiO₂-δ : Fe films exhibited p-type character but the observed ferromagnetism turns out to be independent of the hole concentration. The room-temperature ferromagnetism can be explained in terms of a direct ferromagnetic coupling between two neighboring Fe³+ ions via an electron trapped in oxygen vacancy in TiO₂-δ : Fe.