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.
