Compositional-driven variations in magnetic, conductivity, and ferroelectric properties of multiferroic BiFeO₃–CoFe₂O₄ composite system

The matrix of multiferroic BiFeO₃ (1 − x) and CoFe₂O₄ (x) as a filler with varying weight fractions (x = 10, 30, 50%) was synthesized by the sol–gel technique. The microstructure reveals that the filler at a critical weight fraction of 30% forms a clustering network that spans the entire system. Temperature-dependent dc resistivity of the composite systems confirms the semiconducting behavior where the large change in resistivity is mainly attributed to scattering by grain boundaries between percolating clusters. The VSM analysis implies that saturation magnetization in composite samples with x = 10% and 50% increases to 17 emu/g and 35 emu/g, respectively. The impedance analysis showed the presence of severe trapped charges that lead to depolarization effect in composites. However, the dielectric loss remains low for all composite systems till 10⁴ Hz with the loss peak appearing around 10⁵ Hz.