Enhanced electrocaloric effect at room temperature in Mn²⁺ doped lead-free (BaSr)TiO₃ ceramics via a direct measurement

(Ba_1−xSr_x)(Mn_yTi_1−y)O₃ (BSMT) ceramics with x = 35, 40 mol% and y = 0, 0.1, 0.2, 0.3, 0.4, 0.5 mol% were prepared using a conventional solid-state reaction approach. The dielectric and ferroelectric properties were characterized using impedance analysis and polarization–electric field (P–E) hysteresis loop measurements, respectively. The adiabatic temperature drop was directly measured using a thermocouple when the applied electric field was removed. The results indicate that high permittivity and low dielectric losses were obtained by doping 0.1–0.4 mol% of manganese ions in (BaSr)TiO₃ (BST) specimens. A maximum electrocaloric effect (ECE) of 2.75 K in temperature change with electrocaloric strength of 0.55 K·(MV/m)^–1 was directly obtained at ~21 ℃ and 50 kV/cm in Ba_0.6Sr_0.4Mn_0.001Ti_0.999O₃ sample, offering a promising ECE material for practical refrigeration devices working at room temperature.