Improved Energy Storage and Electrocaloric Properties in Sm³⁺- and Fe³⁺-Substituted BCZT Ceramics

Polycrystalline ceramics with the composition 0.45BaTi_0.80Zr_0.20O₃-0.55Ba_0.69Ca_0.30Sm_0.01Ti_0.99Fe_0.01O₃ were prepared using the solid-state reaction route. The phase formation of the prepared sample was confirmed by x-ray diffraction (XRD) study. The temperature-dependent dielectric permittivity (ε) showed a diffuse phase transition. The observance of ferroelectricity at temperatures above the Curie temperature (T_C) suggests the presence of nano-polar regions in the sample. The efficiency (ƞ), recoverable energy density (W_rec), and loss (W_loss) were determined from the P–E loops. The efficiency (ƞ) increased with an increase in temperature, while W_loss showed a reverse trend. The measured value of W_rec was 0.10 J/cm³, and a value of 94% was found for ƞ. The electrocaloric effect (ECE) was studied using the indirect method, and an adiabatic change in temperature (ΔT) of 0.34 K was found at 25 kV/cm with an electrocaloric coefficient = 0.0136 K cm kV⁻¹. These results suggest that this composition can be used in energy storage and electrocaloric applications.