Large electrocaloric effect in lead-free ferroelectric Ba_0.85Ca_0.15Ti_0.9Zr_0.1O₃ thin film heterostructure

A large electrocaloric effect is reported in a strain-engineered Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCZT) thin film heterostructure driven by the near room-temperature electro-structural phase transition. An epitaxial BCZT/La0.7Sr0.3MnO3 (BCZT/LSMO) was grown on single-crystal SrTiO3 (100) substrate using pulsed laser deposition. In-depth x-ray diffraction and spectroscopic analyses revealed single-crystalline nature stoichiometric growth of heterostructure. Both temperature dependent dielectric measurements broad second-order-type transition 430 K BCZT/LSMO From detailed theoretical experimental data, it confirmed that around second-order nature, unlike first-order observed bulk BCZT materials. Thermodynamic polarization an unprecedently adiabatic change 13.5 at under field 1000 kV cm−1, hitherto unobserved lead-free material. Extremely ΔT(T) curves over wide working range temperatures (330 < T 480 K) resulted enhanced relative cooling powers, which are higher than those so far most We propose interfacial strain-induced tetragonal distortion layer gives rise to these effects system. The demonstration may open up new pathways toward design artificial heterostructures for eco-friendly solid-state applications.