Comprehensive evaluation of electrocaloric effect and fatigue behavior in the 0.9Pb(Mg_1/3Nb_2/3)O₃–0.1PbTiO₃ bulk relaxor ferroelectric ceramic

Electrocaloric refrigeration shows potential as a viable alternative to vapor-compression and/or thermo-electric refrigeration. One of the main challenges that need to be addressed in electrocaloric technology is the fatigue behavior of electrocaloric materials, in terms of both structural and functional aspects. Here, a comprehensive evaluation of the fatigue behavior of the 0.9Pb(Mg_1/3Nb_2/3)O₃–0.1PbTiO₃ (PMN-10PT) bulk relaxor ferroelectric (or shortly relaxor) ceramic at room temperature is performed. First, the temperature-change dependence on the slew rate was studied. It is shown that the adiabatic conditions are well approached at the slew rate above 1 kV s⁻¹, at which the adiabatic temperature change of 1.3 K was measured at the electric field change of 90 kV cm⁻¹. Then, the durability limits (i.e., the fatigue life) of ten PMN-10PT samples were investigated during unipolar electric field cycling. The results showed that the material could withstand up to 10⁶ cycles at the electric field change of 90 kV cm⁻¹ with only minor degradation of the functional properties (less than 5% of the maximum adiabatic temperature change). Hence, PMN-10PT can be considered as a promising material for use in an electrocaloric cooling device, but some critical issues that caused premature failure of several samples would need to be further addressed and improved.