Phase state and structure of ferroelectric ceramics under irradiation

Radiation of different types (γ-rays, electrons, neutrons) and fluence has been used to study the defect processes as well as the change of physical parameters in PLZT X/65/35 (X=4.5-11 at.%) ceramics. A gradual shift of extinction edge to longer wavelengths, reduction of polarization and ε values, and a progressive diffusion of the phase transition including a defect-stimulated phase transformation from the rhombohedral to quasicubic structure in PLZT 6.5-8.5/65/35 compositions with the increase of irradiation fluence are observed in neutron irradiated PLZT ceramics. The prevalence of internal bias field or radiation-induced random field determining the changes of dielectic characteristics in PLZT materials is controlled by La concentration. A neutron fluence of 2.10¹⁸ n/cm² is close to critical for PLZT ceramics.