Measuring lead scandium tantalate phase transition entropy by infrared camera

Using an infrared camera, we measured the latent heat of the first order phase transition in lead scandium tantalate at different applied electric fields. The entropy change value of 3.4 J kg_ 1 K_ 1 is consistent with differential scanning calorimetry measurements. The advantage of such an approach stems from the possibility to obtain both adiabatic temperature change and latent heat of the phase transition material only with an infrared camera or a thermocouple. This may prove useful for a systemic characterization of first order electrocaloric materials

Giant electrocaloric materials energy efficiency in highly ordered lead scandium tantalate

Electrocaloric materials are promising working bodies for caloric-based technologies, suggested as an efficient alternative to the vapor compression systems. However, their materials efficiency defined as the ratio of the exchangeable electrocaloric heat to the work needed to trigger this heat remains unknown. Here, we show by direct measurements of heat and electrical work that a highly ordered bulk lead scandium tantalate can exchange more than a hundred times more electrocaloric heat than the work needed to trigger it. Besides, our material exhibits a maximum adiabatic temperature change of 3.7K at an electric field of 40kVcm(-1). These features are strong assets in favor of electrocaloric materials for future cooling devices. The intrinsic efficiency of electrocaloric materials has been largely overlooked. Here, the authors use the parameter materials efficiency as the figure of merit to rank caloric materials, reporting on the materials efficiency of highly ordered bulk lead scandium tantalate PST