Magnetic and diffusive nature of LiFePO4 investigated by muon spin rotation and relaxation

Article

关键词: POSITIVE-ELECTRODE MATERIALS;    LITHIUM DIFFUSION;    LI+ DEFECTS;    VISUALIZATION;    CONDUCTIVITY;    COEFFICIENT;    CHEMISTRY;    LICOO2;   

DOI  :  10.1103/PhysRevB.84.054430

来源: SCIE

【 摘 要 】

In order to elucidate the magnetism and Li diffusion in LiFePO4, we have measured muon-spin rotation and relaxation (mu+SR) spectra for the polycrystalline LiFePO4 sample in the temperature range between 1.8 and 500 K. Below T-N similar to 52 K, two oscillatory signals together with one fast relaxation signal were clearly found in the zero-field (ZF) mu+SR spectrum. The three signals are reasonably explained using an antiferromagnetic (AF) spin structure proposed by neutron measurements, because electrostatic potential calculations suggests multiple different muon sites in the LiFePO4 lattice. However, the AF ordered moment estimated from mu+SR was about 3/4 of that reported by neutron, probably due to a different time window between the two techniques. In the paramagnetic state, ZF and longitudinal-field (LF) mu+SR spectra exhibited a dynamic nuclear field relaxation. From the temperature dependence of the field fluctuation rate, a diffusion coefficient of Li+ ions (D-Li) at 300 K was estimated about 3.6 x 10(-10) cm(2)/s, assuming that diffusing Li+ ions jump between the regular site and interstitial sites.

【 授权许可】

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