Maxwell-Wagner characterization of dielectric relaxation in Ni0.8Zn0.2Fe2O4/Sr0.5Ba0.5Nb2O6 composite

Dense composites were prepared through incorporating the dispersed Ni0.8Zn0.2Fe2O4 ferromagnetic particles into Sr0.5Ba0.5Nb2O6 ferroelectric matrix. Extrinsic dielectric relaxation and associated high permittivities of the materials are reported in the composites. We used an ideal equivalent circuit to explain electrical responses in impedance formalism. A Debye-like relaxation in the permittivity formalism was also found. Interestingly, real permittivity (epsilon') of the sample containing 30% Ni0.8Zn0.2Fe2O4 shows obvious independence of the temperature at 100 kHz. Dielectric relaxation and high-epsilon' properties of the composites are explained in terms of the Maxwell-Wagner (MW) polarization model. (c) 2005 Elsevier Ltd. All rights reserved.