Control multiple electrocaloric effect peak in Pb(Mg1/3Nb2/3)O3-PbTiO3 by phase composition and crystal orientation

This paper demonstrates the effect of phase composition and crystal orientation on the electrocaloric effect (ECE) in Pb(Mg1/3Nb2/3)O3-PbTiO3 ceramics and single crystals. The ECE features are closely related to phase diagram. Each ECE peak refers to a transition between rhombohedra, tetragonal, and cubic phases. The samples near morphotropic phase boundary have two ECE peaks corresponding to rhombohedra-tetragonal and tetragonal-cubic transitions, the latter induces large ECE of ΔT = 0.60 K (@20 kV/cm) in ceramics and ΔT = 0.69 K (@10 kV/cm) in 〈001〉 single crystal. Different orientations of single crystal change both ECE value and position, where 〈001〉-orientation works for tetragonal-cubic ECE peak and 〈111〉-orientation for rhombohedra-tetragonal peak.