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 (approximate to 1 mu C/cm(2) K) 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 degrees polarization switching and is, therefore, similar in nature to an extrinsic piezoelectric effect. (c) 2007 American Institute of Physics.