Influence of Sr/Ba ratio on the dielectric, ferroelectric and pyroelectric properties of strontium barium niobate ceramics

Sr_xBa_1-xNb₂O₆ (with x=0.50, 0.45, 0.40 and 0.30) ceramics were synthesized by conventional solid-state method and sintered at 1350 °C for 3 h. The phase structure, microstructure, dielectric, ferroelectric and pyroelectric properties of obtained ceramics were systematically investigated. Pure tungsten bronze phase could be obtained in all ceramics. The dielectric characteristics showed that SBN ceramic was a relaxor with strong diffuse phase transition and weak frequency dispersion. As Sr molar fraction x increases from 0.30 to 0.50, the transition temperature T_C decreased linearly while the diffusivity parameter γ declined from 1.88 to 1.68. The saturated polarization, remnant polarization and pyroelectric coefficient were also found to be enhanced in SBN ceramics with increasing Sr content. The pyroelectric coefficient of about 2×10 ^-8 C/cm²K can be obtained for polarized SBN50 ceramics at room temperature.