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    题名: 以X光吸收光譜研究Pr與Yb摻雜之Ca3Co4O9+δ之電子結構
    其它题名: The electronic structure of Pr and Yb doped Ca3Co4O9+δ studied by x-ray absorption spectroscopy
    作者: 陳楚遒;Chen, Chu-ciou
    贡献者: 淡江大學物理學系碩士班
    張經霖
    关键词: X光吸收光譜;熱電材料;Ca3Co4O9;XANES;thermoelectric material;Ca3Co4O9
    日期: 2010
    上传时间: 2010-09-23 16:05:50 (UTC+8)
    摘要: 本論文是利用X光吸收光譜研究Pr與Yb摻雜之Ca3Co4O9+δ之電子結構。在以Pr部份取代Ca的系統中，由Co K-edge 和Ca L3-edge發現Co 4p與Ca 3d空軌域在摻雜之後均減少，而由Co L3-edge和O K-edge發現Co 3d與Co 3d-O2p空軌域在摻雜之後均增加，推測電子會由O原子轉移到Ca 3d空軌域，且電子由Co 3d與O 2p混成軌域轉移到Co 4p空軌域。在以Yb部份取代Ca的系統中，由Ca L3-edge發現Ca 3d空軌域在摻雜之後均減少，由O K-edge發現Co 3d-O2p空軌域在摻雜之後均增加，而由Co K-edge和Co L3-edg發現Co 4p和Co 3d空軌域變化較不明顯，推測電子會由O原子轉移到Ca 3d空軌域，且電子由Co 3d與O 2p混成軌域轉移到Co 4p空軌域的趨勢較不明顯。由Co L3-edge發現Co 3d空軌域與電阻率是相關的。Co的平均價數為+3.37價。
    We have performed x-ray absorption spectroscopy (XAS) study on the electronic structure of Pr and Yb doped Ca3Co4O9+δ. In Pr-doped samples, the variation of the intensities of Co K-edge and Ca L3-edge spectra indicate that the Co 4p and Ca 3d unoccupied state decreased by Pr doping. From Co L3-edge and O K-edge spectra we observe that the Co 3d and Co 3d-O2p unoccupied state were increased by Pr doping. The electronic transferred from O 2p to Ca 3d state and electronic transferred from Co 3d-O2p hybridization state to Co 4p state are possible. In Yb-doped samples, the variation of the intensities of Ca L3-edge spectra indicate that the Ca 3d unoccupied state decreased by Yb doping. The variation of the intensities of O K-edge spectra indicate that the Co 3d-O2p unoccupied state increased by Yb doping. From Co K-edge and Co L3-edge spectra we observe that the variation of Co 4p and Co 3d unoccupied state were unapparent by Yb doping. The electronic transferred from O 2p to Ca 3d state and electronic transferred from Co 3d-O2p hybridization state to Co 4p state are possible. From Co L3-edge, the results indicate that Co 3d unoccupied state is related to resistivity of Ca3-xMxCo4O9+δ(M=Pr, Yb). The average valence of Co in the compounds Ca3-xMxCo4O9+δ(M=Pr, Yb) are about 3.37+.
    显示于类别:[物理學系暨研究所] 學位論文

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