Nonmagnetic insulator state in Na1CoO2 and phase separation of Na vacancies -: art. no. 186405

被引：42

作者：

de Vaulx, C

Julien, MH

Berthier, C

Horvatic, M

Bordet, P

Simonet, V

Chen, DP

Lin, CT

机构：

[1] Univ Grenoble 1, Spectrometrie Phys Lab, F-38402 St Martin Dheres, France

[2] CNRS, UMR5588, F-38402 St Martin Dheres, France

[3] CNRS, Grenoble High Magnet Field Lab, F-38042 Grenoble, France

[4] CNRS, Lab Cristallog, F-38042 Grenoble, France

[5] CNRS, Lab Louis Neel, F-38042 Grenoble, France

[6] Max Planck Inst Solid State Res, D-70569 Stuttgart, Germany

来源：

PHYSICAL REVIEW LETTERS | 2005年 / 95卷 / 18期

关键词：

D O I：

10.1103/PhysRevLett.95.186405

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

Crystallographic, magnetic, and NMR properties of a NaxCoO2 single crystal with x similar or equal to 1 are presented. We identify the stoichiometric Na1CoO2 phase, which is shown to be a nonmagnetic insulator, as expected for homogeneous planes of Co3+ ions with S=0. In addition, we present evidence that, because of slight average Na deficiency, chemical and electronic phase separation leads to a segregation of Na vacancies into the well-defined, magnetic, Na0.8CoO2 phase. The importance of phase separation is discussed in the context of magnetic order for x similar or equal to 0.8 and the occurrence of a metal-insulator transition for x -> 1.

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页数：4

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