Room-temperature electrocaloric effect in (1-x)Ba_(0.67)Sr_(0.33)TiO_3-xBa_(0.9) Ca_(0.1)Ti_(0.9)Zr_(0.1)O_3 ceramics under moderate electric field

摘要

The electrocaloric effect (ECE) was investigated in (1− x )Ba~(0.67)Sr~(0.33)TiO~(3)– x Ba~(0.9)Ca~(0.1)Ti~(0.9)Zr~(0.1)O~(3)(BST– x BCTZ, x  = 0, 0.05, 0.1 and 0.2) ceramics synthesized using citrate–nitrate combustion derived powders. The dielectric spectroscopy revealed that the phase transition temperature increases with increasing x . The ECE was calculated using the Maxwell relation based on the P – E hystersis loops. The addition of BCTZ has notable effect on the microstructure and ECE of ceramic samples. The most promising electrocaloric temperature change (△ T ) of 0.74 K and electrocaloric responsivity (△ T /△ E ) of 0.247 × 10_(−6) K m V_(−1)were obtained in BST–0.05BCTZ ceramic under a moderate electric field of 30 kV/cm near cubic-to-tetragonal phase transition temperature.