Impedance characteristics of Pb(Fe2/3W1/3)O3-BiFeO3 composites

A single phase formation of PFW (Pb(Fe2/3W1/3)O-3)-BFO (BiFeO3) composites prepared by mechanical activation, followed by mixed oxide method was checked by an X-ray diffraction technique. Detailed studies of the impedance parameters suggest that addition of small amount of multiferroic BFO (10%) in PFW matrix produces a low frequency dielectric dispersion (i.e., relaxor characteristics) in the composite phase. Non-Debye type of relaxation phenomena has been observed in the PFW-BFO composites. The higher value of epsilon' at the lower frequency is explained on the basis of the Maxwell-Wagner (MW) polarization model. Complex impedance analysis enable us to separate grain and gain boundary contributions of materials, and it is found that grain boundary resistance is greater than grain resistance irrespective of composition at higher temperatures. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.