Ba‐Modified Bi–Na–Sr Titanate: Exploring Structural, Dielectric, and Electrocaloric Properties for Cooling Applications

The present work reports the structural, dielectric, and electrocaloric properties of Ba‐doped (Bi 0.5 Na 0.5 ) 0.8 Sr 0.2 TiO 3 (BNST) synthesized by the solid‐state reaction route. Rietveld refined X‐ray diffraction data is used to analyze the influence of Ba doping on the lattice parameters, crystallite size, and lattice strain of BNST. The dielectric characteristics of the Ba‐doped BNST samples are analyzed in terms of complex permittivity, AC conductivity, and complex impedance. The dynamic properties of dipoles and the conduction charges are investigated from the frequency‐dependent (100 Hz–1 MHz) dielectric response. Electrocaloric properties are assessed by the indirect method using the Maxwell equation. Polarization of pure and Ba‐substituted BNST varies in a complex manner as a function of temperature leading to positive and negative electrocaloric effects in different temperature ranges within room temperature‐160 °C, beneficial for exploiting the increasing and decreasing, both, cycles of the applied electric field for producing cooling effect. The dipolar entropy is consistent with the literature.