Electrocaloric Effect in 0.85PMN-0.15PT Thin Films Deposited by Pulsed Laser Deposition

The electrocaloric effect (ECE) of 0.85PbMg(1/3)Nb(2/3)O(3-)0.15PbTiO(3) (0.85PMN-0.15PT) thin films deposited on (111) Pt/TiO2/SiO2/Si substrate by pulsed laser deposition (PLD) has been calculated. The reversible adiabatic temperature was calculated indirectly using the Maxwell's relation Delta T = -T/C rho integral(E2)(E1) (partial derivative P/partial derivative T)(sigma,E)dE. Permittivity and P-E measurements show an anomaly at 11 degrees C on heating only. This anomaly previously reported are claimed to arise due to the PNR depolarization upon heating. The absence of this anomaly during cooling suggests that no structural phase transition takes place. A negative electrocaloric effect is observed which is explained by the increase in the entropy term.