![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
The results of electron-spin-resonance (ESR) investigation of ferroelectric 1.8/65/35 and antiferroelectric 2/95/5 optically transparent ceramics Pb1−yLa1−yZr1−xTixO3 (PLZT) in a temperature region 20–300 K after light irradiation with wavelength 365–725 nm are presented. After ultraviolet irradiation at low temperature (T<50 K) paramagnetic centres of Ti3+, Pb3+ and Pb+ were observed. It was shown that Ti3+ and Pb3+ are created in regular lattice sites perturbed by La3+ (La3+ mainly substitutes for Pb2+ and partially for Ti4+) by trapping carries from the conduction or valence band. The temperature interval of stability of these centres as well as their thermal ionisation energies were obtained. The Pb3+ and Pb+ create deep local levels, they are thermally stable up to room temperature in the PLZT 2/95/5. Process of migration of localised carriers was studied for both types of ceramics. It was shown that with temperature increasing or after red light illumination the electrons. ionised to the conduction band from Ti3+, are recaptured by deeper lead centres, preventing carriers drift and appearance of the photoconductivity. The role of localised charges in electrooptical phenomena, which exist in PLZT ceramics, is discussed.