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

Dense composites were prepared through incorporating the dispersed Ni_0.8Zn_0.2Fe₂O₄ ferromagnetic particles into Sr_0.5Ba_0.5Nb₂O₆ 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 (ε′) of the sample containing 30% Ni_0.8Zn_0.2Fe₂O₄ shows obvious independence of the temperature at 100 kHz. Dielectric relaxation and high-ε′ properties of the composites are explained in terms of the Maxwell-Wagner (MW) polarization model.