Direct measurement of electrocaloric effect in lead-free Ba(Sn x Ti 1-x )O 3 ceramics
Résumé
In this study, we report on investigation of the electrocaloric (EC) effect in lead-free Ba(SnxTi1-x)O3(BSnT) ceramics with compositions in the range of 0.08x0.15 by the direct measurementmethod using a differential scanning calorimeter. The maximum EC temperature change,DTEC-max¼0.63 K under an electric field of 2 kV/mm, was observed for the composition withx¼0.11 at44C around the multiphase coexistence region. We observed that the EC effect also peaks at tran-sitions between ferroelectric phases of different symmetries. Comparison with the results of indirectEC measurements from our previous work shows that the indirect approach provides reasonable esti-mations of the magnitude of the largest EC temperature changes and EC strength. However, it fails todescribe correctly temperature dependences of the EC effect for the compositions showing relaxor-like behaviour (x¼0.14 and 0.15) because of their non-ergodic nature. Our study provides strongevidence supporting that looking for multiphase ferroelectric materials can be very useful to optimizeEC performance
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