Dielectric properties Ca-substituted barium strontium titanate ferroelectric ceramics

The dielectric and ferroelectric properties of Ba1−xSrxTiO3 (BST) (x=0.10,0.20,0.30,0.40x=0.10,0.20,0.30,0.40 and 0.60) ceramics and Ba1−2xSrxCaxTiO3 (BSCT) (x=0.10,0.20,0.30)(x=0.10,0.20,0.30) ceramics have been investigated. The low temperature phase transitions of BST ceramics vanish after Ca2+ substitution while the high temperature transition is diffused and relaxed, which becomes more obvious with increasing xx. Ca2+ substitution obviously decreases the dielectric constant maximum, KmKm, of BST ceramics and changes the temperature of dielectric constant maximum, TmTm, of BST ceramics. The shift of TmTm in BST is attributed mainly to the Sr2+ and Ba2+ concentration. BST ceramics exhibit almost normal ferroelectric characteristics, while a typical relaxor behavior was observed in BSCT ceramics. The relaxor behavior observations may be understood by a random electric field induced domain state.