Crystal Structure, Electric and Magnetic Properties of Layered Cobaltite β-NaxCoO2

✍ Scribed by Yasuhiro Ono; Ryuji Ishikawa; Yuzuru Miyazaki; Yoshinobu Ishii; Yukio Morii; Tsuyoshi Kajitani

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 341 KB
• Volume: 166
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2002.9578

✦ Synopsis

The layered oxide thermoelectric material -Na 0.67 CoO 2 has been studied by powder neutron di4raction, electric and magnetic measurements. This compound includes an edge-sharing CoO 6 slab and a highly vacant Na ؉ sheet in a unit cell (space group symmetry C2/m, a ‫؍‬ 4.9023(4) A s , b ‫؍‬ 2.8280(2) A s , c ‫؍‬ 5.7198(6) A s and ‫؍‬ 105.964(6)3 at 300 K). The evaluated formal valence of cobalt ion, ؉3.33(1), is ascribed to the coexistence of Co 3؉ and Co 4؉ in the ratio 2:1. Polycrystalline -Na 0.67 CoO 2 , a p-type thermoelectric material, exhibits metallic behavior of the electric resistivity below 300 K. The Curie+Weiss-type magnetic susceptibility indicates antiferromagnetic interactions between magnetic cobalt ions in the edge-sharing CoO 6 slab.

2002 Elsevier Science (USA)