Electronic and local atomic structures of (La1−xPrx)0.85Zr0.15MnO3 studied by x-ray absorption spectroscopy
Electronic and local atomic structures of (La1−xPrx)0.85Zr0.15MnO3 studied by x-ray absorption spectroscopy
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DOI：
10.1088/0953-8984/17/26/017
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发表时间：
2005-06
期刊：
影响因子：
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通讯作者：
K. Krishna Kumar;J. Chiou;H. Tsai;C. Pao;J. Jan;P. Hsu;D. Ling;F. Chien;W. Pong;M. Tsai;J. F. Lee
中科院分区：
文献类型：
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作者：
K. Krishna Kumar;J. Chiou;H. Tsai;C. Pao;J. Jan;P. Hsu;D. Ling;F. Chien;W. Pong;M. Tsai;J. F. Lee
测量了x=0、0.0 5、0.1、0.15和0.2的(La1−xPrx)0.85 Zr0.15MnO(LPZMO)的MnL3，2-，K-，OK-和PrM5，4-边X射线吸收近边结构(XANES)谱，研究了Pr取代对其电子结构的影响。对LPZMO的L3、2和K边谱的分析表明，LPZMO是一个电子掺杂体系。发现Pr取代增加了Mn离子的平均有效电荷，并在MnL3，2边XANES谱中诱导了一个额外的未占据的多数自旋(自旋)Eg亚带。MnL3，2-，OK-和PrM5，4-边XANES结果表明，La离子被较小的Pr离子取代改变了O2p-Mn3d和O2p-Pr4f杂化状态。扩展X射线吸收精细结构(EXAFS)分析表明，由于Pr的取代，Mn离子周围的局域原子结构发生了明显的变化。XANES和EXAFS分析表明，MnO_6八面体有小的变形或晶格中的无序，这可能是由于载流子局域化和/或Mn离子有效正电荷的增加所致。
Mn L3,2-, K-, O K- and Pr M5,4-edge x-ray absorption near-edge structure (XANES) spectra of (La1−xPrx)0.85Zr0.15MnO3 (LPZMO) with x = 0, 0.05, 0.1, 0.15 and 0.2 were measured to study the electronic structure and the effect of Pr substitution. An analysis of Mn L3,2- and K-edge spectra indicates that LPZMO is an electron-doped system. Pr substitution is found to increase the average effective charge of Mn ions and to induce an additional unoccupied majority spin ( spin) eg subband in the Mn L3,2-edge XANES spectrum. Mn L3,2-, O K- and Pr M5,4-edge XANES results demonstrate that the substitution of La ions by smaller Pr ions changes O 2p–Mn 3d and O 2p–Pr 4f hybridized states. Extended x-ray absorption fine structure (EXAFS) analysis at the Mn K edge reveals clear changes in local atomic structure around Mn ions due to the Pr substitution. XANES and EXAFS analyses show a small distortion in the MnO6 octahedron or a disorder in the lattice, which may be due to localization of charge carriers and/or the increased effective positive charge of Mn ions.