Study of the Electrocaloric Effect in the Relaxor Ferroelectric Ceramic 0.75PMN-0.25PT

摘要

Electrocaloric (EC) cooling based on the ability of materials to change temperature by applying an electric field under adiabatic conditions is a relatively new and challenging direction in ferroelectrics research. Analytical and simulation data for the electrocaloric effect (ECE) in 0.75Pb(Mg1/3Nb2/3)O-3-0.25PbTiO(3) (0.75PMN-0.25PT) bulk ceramic samples are reported. The adiabatic temperature change (Delta T) due to a change of the external electric field has been calculated indirectly from the entropy change. The temperature change increases with an increase in the applied electric field and reaches a maximum of 2.1 K in 25 kV/cm electric field shift near the Curie temperature of 398 K; that is, the cooling Delta T per unit field (MV/m) is 0.896 x 10(-6) m K/V. This value is significantly large for bulk ceramics and makes the compound promising for room-temperature electric cooling applications.