Reduction of the electrocaloric entropy change of ferroelectric PbZr1-xTixO3 epitaxial layers due to an elastocaloric effect

We report laser-based direct measurements of the pyroelectric and electrocaloric effects of PbZr1-xTixO3 epitaxial layers as a function of temperature and electric field. By evaluating the differences between the total pyroelectric and electrocaloric coefficients, we determine the secondary contribution to the electrocaloric effect that is created by a combination of piezoelectric and elastocaloric effects. The secondary contribution to the electrocaloric coefficient has the opposite sign as the primary effect and therefore reduces the overall entropy change of PbZr1-xTixO3 in an electric field. The absolute magnitude of the secondary effect is comparable to the primary effect at elevated temperatures of approximate to 200 degrees C.