Direct Measurements of the Giant Electrocaloric Effect in Soft and Solid Ferroelectric Materials

The giant electrocaloric (EC) effect is of great importance for application in cooling or heating devices of new generation, which would be friendlier for environment. Recent predictions of the existence of the giant EC effect in polymeric and inorganic ferroelectric relaxors are based solely on the indirect measurements of the electric polarization and not on a direct measurement of the EC effect itself. Here a method and analysis of direct measurements of the giant EC effect in various soft and solid ferroelectric materials in the form of thick and thin films is presented. The field dependence of the EC effect is shown for PbMg1/3Nb2/3O3 (PMN) ceramics and P(VDF-TrFE) (68/32 mol%) copolymers.