Preparation, characterization and dielectric properties of Sr5RTi3Ta7O30 (R=Pr and Eu) ferroelectric ceramics

Polycrystalline samples of Sr5PrTi3Ta7O30 (SPTT) and Sr5EuTi3Ta7O30 (SETT) compounds were prepared by high-temperature solid-state reaction method and their formation, structure and dielectric properties were studied. They are found to be ferroelectric phase of filled tetragonal tungsten bronze (TB) structure at room temperature and undergoes diffuse type of ferroelectric-paraelectric phase transition around 34 °C and 31 °C, respectively. At 1 MHz SPTT exhibits high dielectric constants of 177 and low dielectric losses of 3.5×10−4 and SETT has high dielectric constants of 125 and low dielectric losses of 2.4×10−3.