Nd3+ and Nb5+ Co‐Substitution Inducing a Large Electrocaloric Response in Na0.5Bi0.5TiO3 Lead‐Free Ceramics

Abstract

Nd3+ and Nb5+ co‐substituted (Na0.5Bi0.49Nd0.01)Ti1–xNbxO3 lead‐free ceramics are synthesized by conventional solid‐state reaction method. The X‐ray diffraction study revealed that NBNT‐Nb‐0 (x = 0.00) ceramics exhibit single phase monoclinic crystal with Cc phase while NBNT‐Nb‐1 (x = 0.00) ceramics exhibited a dual phase with coexistence of monoclinic and tetragonal systems. The temperature‐dependence dielectric study revealed the existence of ferroelectric and antiferroelectric transformations in two independent regions. Further temperature‐dependent strain vs. electric field measurements strengthen the ferroelectric to antiferroelectric transformation in the present ceramics. The induced electrocaloric effect (ECE) response showed that a significant change in temperature (ΔT) is obtained at 50 kV cm−1 fields: about 0.69 K for NBNT‐Nb‐0 and 0.81 K for NBNT‐Nb‐1 ceramics, respectively. The maximum isothermal entropy change (ΔS) is found to be 0.95 and 1.02 Jkg−1 K−1 for NBNT‐Nb‐0 and NBNT‐Nb‐1 ceramics obtained at 50 kV cm−1, respectively. The simultaneous presence of ECE response and isothermal change in entropy (ΔS) is an open window for great potential applications in the field of electronic devices.