Aging and Memory Effects in PLZT 8/65/35 Ceramics Modified with 3d Transition-Metal Ions

The temperature and frequency dependencies of the dielectric susceptibility in relaxor electro-optical PLZT 8/65/35 modified with 3d transition-metal ions (Mn, Fe, Co, Ni) measured to study the aging and memory effects are reported. The studies of aging at room temperature show that 3d admixtures (Me) in PLZT 8/65/35 ceramics at small to medium concentration range (Me < 1.0wt.%) change the depth of dispersion, the aging amplitude and the temperature range of the memory effect. At admixture concentrations Me 1.0wt% the aging and memory effect are significantly reduced (or eliminated).The obtained results suggest that aging effects are determined by two substantial acceptor effects of the introduced ions: 1) formation of Me2+- V-O (oxygen vacancy) dipoles and 2) Jahn-Teller effect.