Relaxor freezing and electric-field-induced ferroelectric transition in a lanthanum lead zirconate titanate ceramics

Transition lines between various phases in the electric-field-temperature p hase diagram of 9/65/35 lanthanum lead zirconate titanate ceramics were det ermined by measurements of the temperature and electric-field-dependent die lectric constant. Above the critical field (E-c) the de bias electric field induces a transition front the relaxor to the ferroelectric phase, while b elow E-c the system exhibits a freezing transition between the ergodic and nonergodic relaxor state. Transition lines are discussed in terms of the sp herical random-bond-random-field model of relaxer ferroelectrics. Measureme nts in the quasistatic temperature regime confirm the prediction of the mod el that the nonlinear dielectric response shows a sharp peak at the freezin g transition temperature.