Coexistence of negative and positive electrocaloric effect in Sr and Nb co-doped Pb(Zr,Ti)O3 ferroelectric ceramics

•Sr and Nb co-doped Pb(Zr,Ti)O3 ferroelectric ceramics were synthesized by a solid-state reaction method.•Rare phenomenon of coexistence of negative and positive electrocaloric effect was found in Sr and Nb co-doped Pb(Zr,Ti)O3 ferroelectric ceramics.•High electrocaloric coefficient of −0.25 K mm kV−1 and 0.43 K mm kV−1 were obtained.•Reason for the coexistence of negative and positive electrocaloric effect was discussed.

The electrocaloric effect has been investigated in Sr and Nb co-doped Pb(Zr,Ti)O3 (PSNZT) ceramics synthesized by conventional solid state reaction. The coexistence of negative and positive electrocaloric effect was revealed in PSNZT ceramics. The electrocaloric response values of −0.38 K at 80 °C and 0.65 K at 180 °C were observed under an electric field of 1.5 kV/mm. The corresponding electrocaloric coefficient values were calculated to be −0.25 K mm kV−1 and 0.43 K mm kV−1 respectively. The mechanism of the coexistence of negative and positive electrocaloric effect was discussed.