High dielectric tunability of ferroelectric (Ba_(1-x),Sr_x)(Zr_(0.1),Ti_(0.9))O_3 ceramics

摘要

(Ba_(1-x),Sr_x)(Zr_(0.1),Ti_(0.9))O_3 (BSZT) ceramics with x = 0, 0.05, 0.15, 0.25, 0.35 and 0.45 were prepared by conventional solid state reaction method. The structural characterization with X-ray diffraction and scanning electron microscopy indicate a monotonical drop in lattice constants and grain size with the increase of Sr concentration. Consequently, the Curie temperature and remnant polarization of the ceramics exhibit a strong compositional dependence. A linear relationship between the Curie temperature and Sr concentration is revealed. At x = 0.45, the BSZT ceramics show substantially high tunability of over 55 % under 20 kV/cm dc electric field with very low dielectric loss value of 0.0025 at room temperature, suggesting the BSZT ceramics could be a promising alternative to traditional (Ba,Sr) TiO_3 ferroelectrics for developing high frequency tunable dielectric devices.