Characterization and electrical properties of sol-gel synthesized (Sr, Pb)TiO3 powders

Y-doped (Sr, Pb)TiO₃ powders were prepared by a sol-gel route as well as the calcination of gel precursors. The results of DTA/TG showed that the thermal decomposition of dry precursors mainly occurred below 600°C. Meanwhile, infrared ray (IR) spectrum meter, X-ray diffraction (XRD) meter and transmission electron microscope (TEM) were used to characterize the synthesized powders, respectively. Using the synthesized powders as starting materials, Sr_0.5Pb_0.5TiO₃ semiconducting ceramics were fabricated at 1050°C. Sample's room temperature resistivity is 1.51 × 10² · cm, its resistivity jumps more than 5 orders of magnitude above the Curie temperature (T_c). With increasing the soaking time, the room temperature resistivity and the negative temperature coefficient of resistance (NTCR) effect below T_c increased, showing the electrical properties of (Sr, Pb)TiO₃ thermistors are obviously affected by PbO loss.