ENERGY PARAMETERS OF THE MIGRATION OF THE BOUND CATION VACANCIES IN LIF-BA2+

LiF doped with 10(-2) mole fraction of Ba2+ impurity concentration was studied using two experimental techniques, namely thermally stimulated depolarization currents and depolarization currents at constant temperature. Both methods gave compatible results indicating the existence of three relaxation mechanisms. The activation enthalpies of reorientation, h(m), and the preexponential factors tau-0 were determined. The estimated parameters h(m) = 0.24 eV, and tau-0 = 6.59 X 10(-5) sec and h(m) = 0.50 eV and tau-0 = 1.78 X 10(-11) sec may be attributed, respectively, to reorientation of ion-vacancy dipoles by means of nearest-neighbor --> next-nearest-neighbor and nearest-neighbor --> nearest-neighbor jumps. A third mechanism with energy parameters h(m) = 0.81 eV and tau-0 = 4.93 X 10(-20) sec is attributed to a cluster.