Isothermal Phase Transitions in Ceramic Lead Zirconate

Constant temperature permittivity measurements of ceramic lead zirconate near 230°C revealed that the paraelectric to ferroelectric, ferroelectric to antiferroelectric, and antiferroelectric to paraelectric phase transitions were isothermal transformations. On heating, the antiferroelectric phase transformed into a paraelectric phase. Cooling produced a transformation from the paraelectric into an intermediate ferroelectric phase which existed over a temperature range of about 5°C. On further cooling, the ferroelectric transformed into the antiferroelectric phase. Thermal expansion, relative permittivity, and dissipation factor data are reported.