2025/07/09 by Karakaya, M., Gurbuz, I., Fulanovic, L. +1
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)
paper · doi:10.48550/arxiv.2507.07290
The electrocaloric properties of BaTiO3-based lead-free ferroelectric materials have been widely investigated. One approach to achieving a large electrocaloric response is to exploit the substantial polarization change associated with the first-order phase transition at the Curie temperature. Following this strategy, we investigated the electrocaloric response of (1-x)BaTiO3-xNa0.5Bi0.5TiO3 (BT-NBT) ceramics for x = 0.05, 0.10, 0.20, and 0.30. In this BT-rich region of the solid solution, it is established that increasing the NBT content enhances the tetragonality of BaTiO3. We show that this increase in tetragonality helps maintain the first-order nature of the phase transition and enables a correspondingly large electrocaloric response, despite the simultaneous enhancement of relaxor ferroelectric character with NBT substitution. A significantly large effective electrocaloric temperature change (ΔTeff) of ~1.65 K was obtained for the x = 0.20 composition under an applied field of 40 kV/cm using direct electrocaloric measurements, in reasonable agreement with the indirect results.