Grain-Size Effects on Diffuse Phase Transitions of Batio3 Ceramics Obtained by Alkoxide Precursors

ABSTRACTBarium titanate ceramics have been obtained by sol-gel methods. The dielectric investigations of these materials revealed the existence of diffuse ferroelectric transitions. By using a phenomenological model, we could demonstrate the existence of a simple relationship between the diffuse character of the transition and the sample grain-size. This effect has been attributed to interactions between charged defects on the grain surfaces and the spontaneous polarization of the material.