Electrocaloric effect in lead-free Ba1-xLn2x/3Ti0.925(Yb0.5Nb0.5)0.075O3 ceramics (Ln = Eu3+, Nd3+, Pr3+ and x = 0, 0.005)

Abstract

This study reports on the electrocaloric effect in lead-free Ba1-xLn2x/3Ti0.925(Yb0.5Nb0.5)0.075O3 ceramics (where Ln = Eu3+, Nd3+, Pr3+), which was evaluated by an indirect method. The electrocaloric temperature change (ΔT) was estimated from the Maxwell relation based on measured P-E hysteresis loops recorded at different temperatures. For x = 0, the electrocaloric temperature change (ΔT) was about 0.052 K (7.95 kV/cm, 326 K), while they were 0.011 K (3.97 kV/cm and 338 K), 0.019 K (3.97 kV/cm and 332.5 K), and 0.622 K (28 kV/cm and 360 K) for the Eu 3+, Nd3+, and Pr3+ doped BaTi0.925(Yb0.5Nb0.5)0.075O3 (x = 0.005), respectively. The electrocaloric responsivity ξ = ΔT/ΔE, as calculated, reveals that the Ba0.995Pr0.005Ti0.925(Yb0.5Nb0.5)0.075O3 (BTYN: Pr3+) ceramic exhibits the largest value, of about 0.222 Kmm/kV, reported so far in the BTYN-based lead-free ceramics. As a result of this finding, the lead-free BTYN: Pr3+ system seems to be one of the best options for future electrocaloric applications as a lead-free alternative to lead-based materials.