Selective spin-state switch and metal-insulator transition in GdBaCo2O5.5 -: art. no. 180405

被引:228
作者
Frontera, C
García-Muñoz, JL
Llobet, A
Aranda, MAG
机构
[1] CSIC, Inst Ciencia Mat Barcelona, E-08193 Barcelona, Spain
[2] CNRS, Lab Magnetisme Louis Neel, F-38042 Grenoble, France
[3] Univ Malaga, Dept Quim Inorgan Cristalog & Mineral, E-29071 Malaga, Spain
关键词
D O I
10.1103/PhysRevB.65.180405
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Ultrahigh resolution synchrotron diffraction data for GdBaCo2O5.5 throw new light on the metal-insulator transition of Co3+ Ba-cobaltites. An anomalous expansion of CoO6 octahedra is observed at the phase transition on heating, while CoO5 pyramids show the normal shrinking at the closing of the gap. The insulator-to-metal transition is attributed to a sudden excitation of some electrons in the octahedra (t(2g)(6) state) into the Co e(g) band (final t(2g)(4)e(g)(2) state). The t(2g)(5)e(g)(1) state in the pyramids does not change and the structural study also rules out a d(3x)(2)-r(2)/d(3y)(2)-r(2) orbital ordering at T-MI.
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页码:1 / 4
页数:4
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