Super-Ionic State Studies in LNTN Solid Solutions by Raman Spectroscopy

Raman studies of the thermal phase transformations and structural disordering preceding transition to the super-ionic state in the Li0.12Na0.88TaуNb1-уO3 solid solution ceramics are reported. Disordering of the structure brought up by the extremely mobile Li+ ions at heating is found to be homogeneous and to proceed gradually. Disorientation and considerable deformation of the BO6 oxygen octahedrons facilitate translational mobility of the Li+ ions. The static disordering of the Nb5+ and Ta5+ sub-lattice caused by tantalum decreases the temperature of the phase transformation and increases the probability of transition to the super-ionic state supposed to occur over a broad temperature rang…