Elastocaloric Effect in PbTiO_3 Thin Films with 180^\circ Domain Structure: A Phase Field Study

The elastocaloric effect of PbTiO_3 thin films with 180^\circ domain structure is studied using the phase field method. The influence of external stress \sigma_33, misfit strain u_\rm m and domain wall energy on the adiabatic temperature change (\Delta T_\sigma) at room temperature are carried out. The calculation results indicate that |\Delta T_\sigma| increases as |\sigma_33| or |u_\rm m| increases. The largest \Delta T_\sigma value of -7.8 K is obtained at \sigma_33=2 GPa and u_\rm m=-0.02. Furthermore, the domain switching behaviors under different gradient coefficients are different, and finally affect the elastocaloric effect in PTO thin films. These results could provide a guide to choose the substrate and the preparation process in experiments.