Abstract
A core-shell microstructure is adopted to account for the unique resistivity-temperature (ρ-T) behavior of (Pb 0.6 Sr 0.4 )TiO 3 materials prepared by the rapid thermal sintering (RTS) process. Instead of a V-shaped temperature coefficient of resistivity (VTCR) with critical temperature (T′ c1 ) at around 220°C, commonly observed for the materials prepared by conventional sintering process, a ρ-T curve with single high T C2 ≅ 440°C is obtained. Moreover, the cooling rate after the RTS process markedly influences the ρ-T behavior. The apparent resistivity and the negative temperature coefficient of resistivity (NTCR) decrease as the cooling rate increases. The critical temperature (T C2 ) for abrupt resistivity jump is insignificantly varied. These phenomena are ascribed to the modification of the thickness of the shell region due to the interdiffusion between the core and shell materials during the cooling stage. A simplified microstructural model is used to simulate the temperature dependence of resistivity and clearly explains the electrical behavior of these RTS samples.