Full metadata record
DC FieldValueLanguage
dc.contributor.author溫智匡en_US
dc.contributor.authorWen, Chih-Kuangen_US
dc.contributor.author林俊源en_US
dc.contributor.authorLin, Jiunn-Yuanen_US
dc.date.accessioned2014-12-12T02:37:28Z-
dc.date.available2014-12-12T02:37:28Z-
dc.date.issued2013en_US
dc.identifier.urihttp://140.113.39.130/cdrfb3/record/nctu/#GT070052712en_US
dc.identifier.urihttp://hdl.handle.net/11536/73259-
dc.description.abstractIn this thesis, X-ray absorption near edge spectroscopy (XANES) was employed to study the valence and spin degree of freedom of transition metal ions in materials. For the case of Ni(NO3)2, the Ni L-edge spectrum indicates divalence nickel in Ni(NO3)2 compounds. Combined with the theoretical calculations, we confirm that the divalent nickel exhibits the high spin state (S=1) in Ni(NO3)2. In the study, NiO (Ni2+, S=1) was used as the standard sample. The spectrum shape differences between NiO and Ni(NO3)2 come from the different local environments. Moreover, we measured room temperature Mn K, L2,3-edge and Co K, L2,3-edge and temperature dependent Co L2,3-edge XANES spectra in PrSrCoMnO6 double perovskites. Our spectra show the Co3+/Mn4+ ionic state in PrSrCoMnO6. With the help of theoretical calculations, we found that the crystal field in CoO6 octahedral is close to the HS-LS transition boundary. The crystal structure in PrSrCoMnO6 was solved at T=300 K and T=12 K, respectively. PrSrCoMnO6 shows an unusual lattice change at low temperatures. The lattice volume and the average Mn-O bond length decrease, but the average Co-O bond length increases at low temperatures. We also find there is a close relationship between CoO6 local environment and Co L-edge spectra line shape. The temperature dependent Co L-edge XAS spectra of PrSrCoMnO6 obviously demonstrate the spin state variation with T, which can be described as the combination of a LS ground state and the triply degenerate HS first excited states.zh_TW
dc.description.abstractIn this thesis, X-ray absorption near edge spectroscopy (XANES) was employed to study the valence and spin degree of freedom of transition metal ions in materials. For the case of Ni(NO3)2, the Ni L-edge spectrum indicates divalence nickel in Ni(NO3)2 compounds. Combined with the theoretical calculations, we confirm that the divalent nickel exhibits the high spin state (S=1) in Ni(NO3)2. In the study, NiO (Ni2+, S=1) was used as the standard sample. The spectrum shape differences between NiO and Ni(NO3)2 come from the different local environments. Moreover, we measured room temperature Mn K, L2,3-edge and Co K, L2,3-edge and temperature dependent Co L2,3-edge XANES spectra in PrSrCoMnO6 double perovskites. Our spectra show the Co3+/Mn4+ ionic state in PrSrCoMnO6. With the help of theoretical calculations, we found that the crystal field in CoO6 octahedral is close to the HS-LS transition boundary. The crystal structure in PrSrCoMnO6 was solved at T=300 K and T=12 K, respectively. PrSrCoMnO6 shows an unusual lattice change at low temperatures. The lattice volume and the average Mn-O bond length decrease, but the average Co-O bond length increases at low temperatures. We also find there is a close relationship between CoO6 local environment and Co L-edge spectra line shape. The temperature dependent Co L-edge XAS spectra of PrSrCoMnO6 obviously demonstrate the spin state variation with T, which can be described as the combination of a LS ground state and the triply degenerate HS first excited states.en_US
dc.language.isoen_USen_US
dc.subjectX光吸收光譜zh_TW
dc.subject過渡金屬zh_TW
dc.subjectX-ray absorption spectroscopyen_US
dc.subjectTransition metalen_US
dc.title以吸收光譜研究八面體結構中過渡金屬價態與自旋態zh_TW
dc.titleSpin configurations and valence state study of transition metal ions in octahedral environment by X-ray absorption spectroscopyen_US
dc.typeThesisen_US
dc.contributor.department物理研究所zh_TW
Appears in Collections:Thesis


Files in This Item:

  1. 271201.pdf

If it is a zip file, please download the file and unzip it, then open index.html in a browser to view the full text content.