Direct and indirect measurement of large electrocaloric effect in barium strontium titanate ceramics

Barium strontium titanate (Ba1-xSrxTiO3-BST) ceramics, where x = 0.05, 0.15, 0.25, and 0.35, was prepared via a solid-state reaction method. The lattice structures and morphologies of the ceramic samples were analyzed using X-ray diffraction and scanning electron microscopy technologies. The dielectric and ferroelectric properties of the BST ceramics were characterized using a precision impedance analyzer and a ferroelectric polarization-electric field (P-E) hysteresis loop tester, respectively. The electrocaloric effect was indirectly calculated using the Maxwell relations and P-E loops as a function of temperature and electrical field, and also directly measured using a computer-controlled thermocouple and high-voltage power supply. An adiabatic temperature change of 1.82 K was procured, indicating a promising potential in the applications as cooling devices.