THERMALLY STIMULATED DEPOLARIZATION CURRENT STUDIES IN SODIUM-DOPED AND BARIUM-DOPED POTASSIUM YTTRIUM FLUORIDE

The results of thermally stimulated depolarization current (TSDC) and electrical conductivity studies of potassium yttrium fluoride (KYF4) c ompound doped with sodium and barium are presented, The TSDCs were mea sured as a function of the polarizing temperature and polarizing field strengths at a constant heating rate of 0.09 K s(-1). The conductivit y studies were carried out in the temperature range 370-835 K with dif ferent dopant concentrations. The variation of the conductivity with t he doping concentration was found to be non-linear. The relaxation par ameters and the activation energies were evaluated. The origin of the TSDC peak in KYF4:Na was attributed to space charge polarization. Howe ver, in the case of KYF4:Ba, in addition to space charge polarization, there is also a small contribution from the dipolar mechanism.