THERMALLY STIMULATED PROCESS IN A CERAMIC IONIC CONDUCTOR BY TSDC TECHNIQUE

Abstract

The thermally stimulated processes in a pyrochlore-type ceramic ionic conductor were examined by the thermally stimulated depolarization current (TSDC) technique. Three polarization processes have been found in the thermogram. The first one, revealed to result from the convolution of three simple processes with approximately similar activation energies value and can be basically attributed to the reorientation of cation-anion dipoles by means of nearest-neighbor (NN) to nearest-neighbor jumps (that is to say, a NN → NN relaxation type). The second process originated most likely also from a dipolar mechanism now involving nearest-neighbor to next-nearest-neighbor relaxation processes (NN→ NNN relaxation type). On the other hand, the third process has been related to a space-charge relaxation, arising from the migration of K+ free-charge carriers. The activation energies and the pre-exponential factors for all these mechanisms were also reported.