Effect of BaTiO3 addition on the microstructure and relaxor ferroelectric properties of Sr0.7Ba0.3Nb2O6 ceramics

A conventional solid-state reaction was used to synthesize (1-x) Sr0.7Ba0.3Nb2O6–xBaTiO3 (0.00≤x≤0.10) ceramics. The phase structure, microstructure, and dielectric and relaxor ferroelectric properties of these ceramics were investigated. Tungsten bronze structure can be observed in ceramics, and addition of BaTiO3 can make the grain size decrease and the porosity increase. The dielectric characteristics show diffuse phase transition phenomena for all samples, which were demonstrated by a linear fit of the modified Curie-Weiss law with γ varying between 1.54 and 1.88. As the BaTiO3 content increases, the transition temperature (TC) decreases gradually and has a minimum value of 37.53 °C at composition x=0.06, and the maximum dielectric constant (εmax) increases gradually from 66 to 3309 and subsequently decreases to 1625 at x=0.10. In addition, the relaxor ferroelectric properties of these ceramics at x=0.8 are consistent with the Volgel-Fulcher relationship; polarization versus electric field (P-E) loops were measured at a different temperature.