Microstructural characteristics and nonequilibrium core-shell phase in (Pb_xSr_1−x)TiO₃ materials and their electrical properties

Abstract

Microstructural characteristics and the corresponding resistivity-temperature (ρ−T) properties of microwave- and conventionalsintered Pb_0.6Sr_0.4TiO₃ materials with positive temperature coefficient of resistivity (PTCR) were investigated in the present work. The specimens prepared by microwave sintering exhibited a single T_c, whereas those prepared using conventional sintering show double T_c behavior. During the microstructural investigations, sintering aids, SiO₂ and TiO₂, showed intriguing liquid phase sintering characteristics in the specimens. Large amounts of Pb-species dissolved in high Si regions, where a nonequilibrium core-shell structure was frequently observed, especially for microwave sintered specimens, which showed very complicated domain arrangements in the grain interiors.

Keywords:

• positive temperature coefficient of resistivity
• microwave sintering
• core-shell structure
• domain arrangements