The emergent technological advancement towards zero-emissions and high efficient ferroelectric refrigeration requires to maintain a large adiabatic temperature change (ΔT) over a wide-temperature span (ΔT_span) resulting from the electrocaloric effect (ECE). However, it is an outstanding challenge to retain simultaneously both ΔT and ΔTspan in ferroelectric materials. Commonly, the ECE effect is determined due to the phase transitions induced by the external electric field and ordered arrangement of dipoles, which results in change of the entropy of the system. In general, normal ferroelectrics with typical first order phase transitions exhibits a large ΔT value near the vicinity of the phase transition but with narrow ΔT_span. Relaxor ferroelectric showing field induced phase transition over a broad range of temperature could be a suitable electrocaloric system. However, the improved temperature stability at the expense of decrease in ECE parameters is still a major shortcoming for their practical applications. Here, we proposed a way to enhance high temperature stability as well as good ECE value around room temperature by designing a lamellar composite structure of three different composition of BaTi_0.92Sn_0.08O₃ (BST8), BaTi_0.88Sn_0.12O₃ (BST12) and BaTi_0.85Sn_0.15O₃ (BST15) system, respectively.

Keeping the practical application, the compositions are chosen such that they exhibit successive phase transitions over a wide temperature span to obtain high ECE value. The dielectric studies reveal a broad peak over a wide temperature range associated with the successive structural phase transitions. Individually, BST8 composition shows sharp phase transitions, whereas BST12 and BST15 composition show diffused kind of phase transition. Rietveld refinement on the X-ray diffraction patterns show that all the compositions are multiphase in nature. The polarization versus electric field (P-E loops) measurements display slimmer P-E loops for higher Sn concentration. The ECE parameters are calculated by employing the Maxwell’s thermodynamic relations using the P-E loops measured at various temperatures. We have obtained ECE parameter ΔT > 0.6 °C at 40 kV/cm over a ΔTspan ~ 55 °C. The experimental results show that a good ECE value with enhanced temperature stability is achieved in lamellar composite structure.