Effects of zirconium on the structural and dielectric properties of (Ba, Sr)TiO3 solid solution

Abstract

The effects of zirconium on (Ba, Sr)TiO3 solid solution are studied by preparing (Ba0.75Sr0.25) (Zry Ti1-y)O3 (BSZT) ceramics with γ ranging from 0 to 0.15. With increased incorporation of zirconium the lattice parameters increase with decreasingc/a ratio, while a linear relationship is found between (a2c)1/3 values and the content of zirconium. The Curie temperature (Tc) is also lowered linearly with increasing γ. The Curie temperature of the (Ba1-xSrx (ZryTi1-y)O3 system can be estimated byTc = 125 − 270x − 350y (°C). Observations of microstructures also show that a small amount of zirconium promotes the grain growth, while a higher content will then inhibit it. Dielectric properties of BSZT dielectrics and BSZT-based boundary layer (BL) capacitors are also correlated to have similar temperature dependence, where the maximum dielectric constant at room temperature is found aty = 0.1.