Ferroelectric, Ferromagnetic, and Magnetoelectric Properties 
of Multiferroic Ni0.5Zn0.5Fe2O4–BaTiO3 Composite Ceramics
Lead-free multiferroic composite ceramics xNi0.5Zn0.5Fe2O4–(1 − x)BaTiO3 (x = 0.2, 0.5, 0.8) with a 0–3-type connection structure have been prepared by a traditional ceramic process. The cubic spinel Ni0.5Zn0.5Fe2O4 phase and the tetragonal perovskite BaTiO3 phase were confirmed by x-ray diffraction. The effect of Ni0.5Zn0.5Fe2O4 ferrite content on ferroelectric and ferromagnetic behavior, and the magnetoelectric coupling effect of the composite ceramics is discussed. With increasing Ni0.5Zn0.5Fe2O4 ferrite content, the saturation magnetization of the composite ceramic increased and the saturation polarization decreased. The magnetoelectric coupling response voltage was observed to decrease rapidly for samples with x = 0.2, then 0.5, then 0.8. The highest magnetoelectric coupling response voltage, measured for 0.2Ni0.5Zn0.5Fe2O4–0.8BaTiO3, was 150 μV, which corresponds to a maximum magnetoelectric coupling voltage coefficient of 109 μV/cm Oe. When x = 0.5, the maximum magnetoelectric response voltage is only 8 μV, and when x = 0.8, no magnetoelectric response voltage is detected because of very large leakage current of the 0.8Ni0.5Zn0.5Fe2O4–0.2BaTiO3 composite ceramic.