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  • 02월 22일 16시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

Vertically Aligned CoFe2O4 and Mn-Substituted CoFe2O4 Nanowires: Effect of Mn Substitution on the Electronic Structures

등록일
2008년 2월 14일 10시 45분 35초
접수번호
1270
발표코드
29P6포 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
발표시간
목 <발표Ⅰ>
발표형식
포스터
발표분야
물리화학
저자 및
공동저자
김창현
고려대학교 소재화학과,
Vertically aligned CoFeO4 and 10% Mn-substituted CoFeO4 nanowires were synthesized by the gas-phase reduction/substitution reaction of pre-grown α-Fe2O3 nanowires. They consisted of perfect single-crystalline cubic structures grown along the [110] direction. The increase of the lattice constant and the significant lower-frequency shift of the Raman peak provide evidence for the effective Mn substitution. We thoroughly investigated their electronic structures using X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and X-ray magnetic circular dichroism. The results showed that as the Mn substitutes, Mn2+/Mn3+ ions occupy the octahedral (Oh) sites, Mn4+ ions form at the Td sites, and a fraction of the Co2+ ions migrate from the Oh sites to the tetrahedral (Td) sites. The magnetization measurement revealed that the Mn substitution reduces the coercivity, which can be explained by this remarkable electronic structure. Furthermore, Mn substitution makes it possible to develop highly sensitive humidity sensors operating at room temperature.

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