Enhanced pyroelectric effect in self-supported films of BaTiO3 with polycrystalline macrodomains

Self-supported films of nanocrystalline BaTiO3 exhibit a two orders of magnitude enhancement of the pyroelectric coefficient (≈1μC∕cm2K) with respect to the value measured for a single BaTiO3 crystal. The enhancement strongly depends on film geometry and appears only in buckled films where ferroelectric grains undergo self-organization into polycrystalline macrodomains. The authors posit that the enhancement of the pyroelectric effect is related to 90° polarization switching and is, therefore, similar in nature to an “extrinsic” piezoelectric effect.