Micro- and macroscopic magnetism on layered cobalt dioxide LixCoO2 (0.1x1)
- 作者：Kazuhiko Mukai ; Jun Sugiyama ; Yutaka Ikedo ; Daniel Andreica ; Alex Amato ; Jess H. Brewer ; Eduardo J. Ansaldo ; Peter L. Russo ; Kim H. Chow ; Kingo Ariyoshi ; Tsutomu Ohzuku
- 关键词：A. Oxides ; D. Magnetic properties ; D. Electrochemical properties ; D. Muon spin resonance (μ ; SR)
- 刊名：Journal of Physics and Chemistry of Solids
- 出版年：2008
- 期刊代码：69_00223697
- 类别：ch
- 出版时间：May-June 2008
- 卷：69
- 期：5-6
- 页码：1479-1482
- 文件大小：442 K
摘要
The magnetism for the electrochemically prepared LixCoO2 samples with 0.1
x1 was investigated by muon-spin rotation/relaxation (μSR) and susceptibility (χ) measurements. The χ(T) curves with H=10 kOe, which correspond to the change in macroscopic magnetism, are almost T-independent down to 
50 K for the x0.44 samples, suggesting that the samples in this x range are Pauli-paramagnetic. For the samples with 0.49x3/4, a cusp is, however, observed around 170 K in their χ(T) curve. Since there are no anomalies in the μSR parameters around 170 K and μSR is sensitive to local magnetic nature, the cusp is most unlikely due to a magnetic transition, but either a spin state transition or a structural phase transition. Furthermore, zero-field μSR time spectra for all the samples mainly show a slow Kubo–Toyabe behavior, indicating that muon spin is mainly depolarized by randomly oriented nuclear moments of 7Li and 59Co. Hence, it was clarified that all the LixCoO2 samples with x<1 are paramagnetic even at 1.8 K, in contrast to NaxCoO2 and KxCoO2.
x1 was investigated by muon-spin rotation/relaxation (μSR) and susceptibility (χ) measurements. The χ(T) curves with H=10 kOe, which correspond to the change in macroscopic magnetism, are almost T-independent down to 50 K for the x0.44 samples, suggesting that the samples in this x range are Pauli-paramagnetic. For the samples with 0.49x3/4, a cusp is, however, observed around 170 K in their χ(T) curve. Since there are no anomalies in the μSR parameters around 170 K and μSR is sensitive to local magnetic nature, the cusp is most unlikely due to a magnetic transition, but either a spin state transition or a structural phase transition. Furthermore, zero-field μSR time spectra for all the samples mainly show a slow Kubo–Toyabe behavior, indicating that muon spin is mainly depolarized by randomly oriented nuclear moments of 7Li and 59Co. Hence, it was clarified that all the LixCoO2 samples with x<1 are paramagnetic even at 1.8 K, in contrast to NaxCoO2 and KxCoO2.