Enhanced multiferroic properties in (1–y)BiFeO3–yNi0.50Cu0.05Zn0.45Fe2O4 composites

• XRD shows coexistance of ferroelectric and ferrimagnetic phases and no third phase.
• The multiferroic composites show enhanced initial permeability and low loss.
• Dielectric constant exhibits excellent high frequency stability.
• Enhanced ME effect (∼38 mVcm−1Oe−1) is observed for 0.8BFO–0.2NCZFO composite.
• ME coupling is strain-mediated.

Multiferroic composites (1–y)BiFeO3–yNi0.50Cu0.05Zn0.45Fe2O4 (y=0.0, 0.1, 0.2, 0.3 and 0.4) are synthesized by the standard solid state reaction method. The X-ray diffraction analysis affirms the formation of both the component phases and also reveals that there is no chemical reaction between them. From the energy-dispersive X-ray spectroscopy study it is observed that the percentage of the elements in the component phases is well consistent with the nominal composition of the composites. Field Emission Scanning Electron Microscopy analysis shows almost homogeneous mixture of the two phases. The real part of the initial permeability increases (up to 67%) and the loss decreases with the ferrite content in the composites which is important in application point of view. Dielectric constant (ε′), loss tangent and AC conductivity are measured as a function of frequency at room temperature. The highest ε′ is obtained for 0.6BiFeO3–0.4Ni0.50Cu0.05Zn0.45Fe2O4 composite. The dielectric dispersion at lower frequency (<105 Hz) is due to the interfacial polarization. The complex impedance spectroscopy is used to correlate between the electrical properties of the studied samples with their microstructures. Two semicircular arcs corresponding to both grain and grain boundary contribution to electrical properties have been observed in all the studied samples. The maximum magnetoelectric voltage coefficient is found to be ∼38 mV cm−1 Oe−1 for the composite with 80% ferroelectric+20% ferrite phases. The present composite might be a promising candidate as multiferroic materials showing effective electric and magnetic properties.