EFFECTS OF THE GRAIN ORIENTATION ON THE ELECTROCALORIC EFFECT OF POLYCRYSTALLINE FERROELECTRICS

Grain orientation in polycrystalline ferroelectrics has an important effect on the properties of the material, such as the electrocaloric effect (ECE). This paper design a BaTiO3 polycrystalline model including four grains, and the effect of grain orientation difference on the ferroelectricity and ECE of polycrystalline ferroelectrics is studied. The results show that the ferroelectricity of polycrystals gradually weakens with the increase of orientation difference, and with the temperature increases, the ferroelectricity gradually loses. The reduction of the grain orientation difference will produce a large adiabatic temperature change near the Curie-Weiss temperature of BaTiO3, about 5.38 K, meanwhile a negative ECE can be observed, about -2.36 K when the orientation difference reaches 45 degrees. This work shows that regulating grain arrangement can obtain a better mechanical-thermal coupling performance than randomly distributed polycrystalline ferroelectrics.