Influence of Finite Size on the Electrocaloric Response in PbTiO₃ Ceramics Near Room Temperature Using Landau Theory

We investigate the influence of grain size on the electrocaloric properties of ferroelectric systems using Landau theory. We study how the phase transformation temperature and electrocaloric property can be tuned by changing the grain size close to the critical size. Our results show that the electrocaloric coefficient at room temperature can be greatly enhanced by controlling the grain size. In particular, we calculate the adiabatic temperature change, ΔT to be ≈2 K with an electric field difference ΔE = 50 kV cm⁻¹ at room temperature in a model for PbTiO₃ ceramics. The results provide an approach to improving the electrocaloric properties at room temperature in experiments by engineering the grain size.