Relationship between Crystal Structures and the Relaxor Property of SrBi₂(Ta_2- V )O₉ Ceramics

Here, V₂O₅ was used to substitute Ta₂O₅ in SrBi₂Ta₂O₉ (SBT) and SrBi₂(Ta_2- V )O₉ (SBTV) ceramics were formed. This study revealed that the substitution of Ta₂O₅ by V₂O₅ enhances the maximum dielectric constant (ε_m), increases the transition temperature, and reduces the sintering temperature of SBT ceramics. The diffraction intensity of c-axis-preferred orientation of SBTV ceramics increases with the increase in V₂O₅ concentration and sintering temperature. Disk-type grains were observed in the SBTV ceramics at higher sintering temperatures. By the Curie-Weiss law and modified Curie-Weiss law, the phase transitions of the SBTV ceramics were discussed. The dielectric properties of SBTV ceramics revealed that the relaxor-type ferroelectric characteristics became more obvious than the normal-type ferroelectric characteristics at high V₂O₅ concentrations and sintering temperatures. Raman spectroscopy was successfully used to study the lattice vibrational modes and structural transitions of SBTV ceramics. The spectra proved that as V₂O₅ was added to SBTV ceramics the octahedral TaO₆ and VO₆ structures exhibited a high frequency mode.