ランタンリチウムタンタレートにおける伝導率の非 Arrhenius 温度依存性

概要

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Non-Arrhenius temperature dependence of bulk dc conductivity was observed in La_<1/3-x>Li_<3x>TaO_3 which are Liion conductors derived from A-site deficient perovskites. In order to discuss the non-Arrhenius conductivity, several parameters relevant to the Li ion dynamics were determined by impedance spectroscopy and ^7Li NMR. The activation energies of the dc conductivity in the high and low temperature ranges were nearly equal to that of the reciprocal correlation time (f_<NMR>) obtained from NMR measurement and that of the crossover frequency (f_p) extracted from a power-law analysis of conductivity spectra, respectively. A change in the activation energy of the dc conductivity occurred in the vicinity of temperature where f_p is equal to f_<NMR>. Because f_p relates to correlated hops of mobile ions and f_<NMR> to non-correlated hops, our result supports Ngai's explanation which premises presence of a microscopic time.
社団法人日本セラミックス協会の論文
2005-04-01