Structural and dielectric properties of strontium doped barium titanate stannate ferroelectric ceramics with diffused phase transition

摘要

12 at. % strontium doped Ba_(1-x)Sr_xTiO_3 (BST, x=0.10, 0.20 and 0.30) ceramics prepared by the conventional mixed oxide method were investigated. Sn doping significantly decreases the peak dielectric constant of BST ceramics and shifts the temperature of the peak dielectric constant to lower temperature for the different compositions. BST exhibits a normal-like ferroelectric behavior while a dielectric relaxation behavior was observed in strontium doped BST, and the degree of the diffuseness and the relaxation of BST ceramics increases after introducing Sn. The results indicate that the selected system exhibits one broad dielectric peak in 12 at. % strontium doped BST ceramics with increasing x, i.e., the two phase transitions in BST ceramics are merged into one broad peak in 12 at. % strontium doped BST ceramics. The abnormal dielectric behavior can be attributed to non-equivalence ions co-substitution to A- and B-site in ABO_3 perovskite structure.