Polymorphic structure evolution and large piezoelectric response of lead-free (Ba,Ca)(Zr,Ti)O_3 ceramics

摘要

The polymorphic structure evolution of (Ba,Ca)(Zr,Ti)O_3 piezoelectric ceramics was investigated by analysis of the in situ X-ray diffraction and dielectric spectra. The results indicated that a confined orthorhombic (O) phase region induced by the approach of the rhombohedral (R) and tetragonal (T) phases existed in an extremely narrow temperature range of (Ba_(0.85)Ca_(0.15))(Zr_(0.1)Ti_(0.9))O_3 composition. The electric properties near the 0-T phase boundaries of (Ba_(0.95)Ca_(0.05))(Zr_(0.05)Ti_(0.95))O_3 and (Ba_(0.85)Ca_(0.15))(Zr_(0.1)Ti_(0.9))O_3 were compared. The results suggested that the confined O phase region is an important factor that contributes to the extremely large piezoelectric response.