Search for memory and return to disorder in potassium-lithium tantalate crystals

Return to disorder, and less frequently memory, have been demonstrated in v arious disordered materials. In order to find the conditions necessary for the observation of these effects, the evolution of the real part epsilon(1) Of the dielectric constant of two disordered paraelectric crystals K1-xLix TaO3 (KLT) has been extensively studied by the means of the capacitance C(T , t) around the beginning and the end of a temperature plateau. The return to disorder and memory effects have not been seen in KTL, in contrast to wh at was recently observed in disordered fenoelectric crystals KTa1-yNbyO3 of a similar family. The variations dC = P(T-0, t(0)) dT + Q(T-0,T- t(0)) dr in the vicinity of the point (T-0, t(0)) are split into a contribution depe nding on temperature only and an isothermal contribution only depending on time. All the results of such an analysis of the features observed in KLT c an be explained by the domain wall model in its original form.