Large electrocaloric strength in the (100)-oriented relaxor ferroelectric Pb[(Ni1/3Nb2/3)0.6Ti0.4]O3 single crystal at near morphotropic phase boundary

Relaxor ferroelectric Pb[(Ni1/3Nb2/3)0.6Ti0.4]O3 (PNNT) single crystal with composition close to the morphotropic phase boundary (MPB) was successfully prepared using the molten salt method. The analysis results of XRD and TEM indicated that the as-grown crystal is of almost pure perovskite phase with coexistence of tetragonal and rhombohedral. Typical relaxor behavior was observed when the crystal was aged. Large electrocaloric strength (ΔT/ΔE) of 44.97 mK cm/kV was obtained near the phase transition temperature of paraelectric to ferroelectric, indicating that PNNT is a promising material for application in cooling system. Moreover, it is found that the aging of point defects may make an important contribution to the electrocaloric performance of the single crystal, in addition to the contribution of the transition of phases induced by the electric field.