Electric-field induced phase transitions in 9/65/35 PLZT ceramics

Transition lines between various phases in the electric-field temperature p hase diagram of 9/65/35 PLZT ceramics were determined by measurements of th e temperature and electric-field-dependent dielectric constant. Above the c ritical field E-c the dc bias electric field induces relaxer to the ferroel ectric (FE) phase transition. Transition lines were found to depend on the direction of the approach - the temperature or de bias field direction - to the FE phase. Also, a strong impact of the electric field on the stability of the FE phase with the increasing temperature was found. Below E-c the s ystem exhibits a transition line between the ergodic and nonergodic relaxer state. The experimental results are compared with the results of a spheric al random bond-random field model of relaxer ferroelectrics.