Electrocaloric effect in (1 - X)PIN-xPT relaxor ferroelectrics

The electrocaloric effect (ECE) is investigated in both relaxor as well as morphotropic composition of (1 - x)Pb(In1/2Nb1/2)O3-xPbTiO3 system. The ECE is analyzed by evaluating the electrocaloric temperature change (ΔT) using thermodynamic Maxwell equation. The relaxor phase (x = 0.15) show an anomalous broadening in ECE and the maximum of ΔT is found to shift from the proximity of depolarization temperature (Td) to around T′m with increase in electric field. However, for morphotropic composition (x = 0.33) a region with negative ΔT is observed below Td along with anomalous broadening in positive ΔT in the proximity of TRT. The maximum value of ΔT obtained for relaxor phase is 0.37 K whereas 0.12 K is observed for morphotropic composition at 225C. The electrocaloric responsivity ξmax is 0.21 mmK/kV for relaxor phase whereas 0.06 mmK/kV is obtained for the morphotropic composition at 18 kV/cm electric field.