Non-Arrhenius conductivity in the fast ionic conductorLi0.5La0.5TiO3:Reconciling spin-lattice and electrical-conductivity relaxations

Abstract

Nuclear magnetic resonance and electrical conductivity measurements are conducted to study the dynamics of the ionic diffusion process in the crystalline ionic conductor ${\mathrm{Li}}_{0.5}{\mathrm{La}}_{0.5}{\mathrm{TiO}}_3.$ dc conductivity shows a non-Arrhenius temperature dependence, similar to the one recently reported for some ionic conducting glasses. Spin-lattice and conductivity relaxations are analyzed in the same frequency and temperature range in terms of the non-Arrhenius dependence of the correlation time. Both relaxations are then described using a single correlation function of the form $f\left(t\right)=\exp \left(-\right(t/\tau {)}^{\beta }),$ with β=0.4 over the whole temperature range.