Dielectric properties of the mixed aurivillius phases MIIBi8Ti7O27 (MII = Ca, Sr, Ba and Pb)

Abstract Ceramic materials have been prepared by natural sintering and hot-forging M II Bi 8 Ti 7 O 27 (M II = Ca, Sr, Ba and Pb) powders synthesized using a molten salt technique. The materials are ferroelectric at room temperature and show strong dielectric anisotropy in connection with the crystal structure. In each case, a double anomaly of the dielectric permittivity was found as a function of temperature. The temperatures at which it occurs are dependent on M II . The origin of this phenomenon is assumed to be closely related to a sequence of phase transitions like those already observed in other mixed Aurivillius phases.