Enhanced Electrocaloric Effect in 0.73Pb(Mg1/3Nb2/3)O-3-0.27PbTiO(3) Single Crystals via Direct Measurement

Electrocaloric properties of [110] and [111] oriented 0.73Pb(Mg1/3Nb2/3)O-3-0.27PbTiO(3)single crystals were studied in the temperature range of 293-423 K. The Maxwell relations and the Landau-Ginsburg-Devonshire (LGD) phenomenological theory were employed as the indirect method to calculate the electrocaloric properties, while a high-resolution calorimeter was used to measure the adiabatic temperature change of the electrocaloric effect (ECE) directly. The results indicate that the directly measured temperature changes of Delta T> 2.5 K at room temperature were procured when the applied electric field was reversed from 1 MV/m to -1 MV/m, which are larger than those deduced pursuant to the Maxwell relation, and even larger than those calculated using the LGD theory in the temperature range of 293-similar to 380 K.