Unconventional charge ordering in Na0.70CoO2 below 300 K -: art. no. 100404

被引:70
作者
Gavilano, JL [1 ]
Rau, D [1 ]
Pedrini, B [1 ]
Hinderer, J [1 ]
Ott, HR [1 ]
Kazakov, SM [1 ]
Karpinski, J [1 ]
机构
[1] ETH Honggerberg, Festkorperphys Lab, CH-8093 Zurich, Switzerland
关键词
D O I
10.1103/PhysRevB.69.100404
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We present the results of measurements of the dc-magnetic susceptibility chi(T) and the Na-23-NMR response of Na0.70CoO2 at temperatures between 50 and 340 K. The chi(T) data suggest that for T>75 K, the Co ions adopt an effective configuration of Co3.4+. The Na-23-NMR response reveals pronounced anomalies near 250 and 295 K, but no evidence for magnetic phase transitions is found in chi(T). Our data suggest the onset of a dramatic change in the Co 3d-electron spin dynamics at 295 K. This process is completed at 230 K. Our results may be interpreted as evidence for either a tendency to electron localization or an unconventional charge-density-wave phenomenon within the Co 3d electron system near room temperature.
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页数:4
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