Synthesis, structural, microstructural and electromagnetic properties of (1 − x) [Ni0.25Cu0.15Zn0.60Fe2O4] + (x) [Na1/3Ca1/3Bi1/3Cu3Ti4O12] composites

In this work, lead-free (1 − x) [Ni0.25Cu0.15Zn0.60Fe2O4] (NCZFO) + (x) [Na1/3Ca1/3Bi1/3Cu3Ti4O12] (NCBCTO) (0.0 ≤ x ≤ 1.0) were synthesized via solid state reaction route and sintered at 1000 and 1050 °C. The phase compositions and surface morphology of the composites were investigated using standard techniques. XRD and FTIR analyses confirmed the successful formation of the composites without any impurity phases. The SEM analysis disclosed that the average grain size was decreased as the NCBCTO content increases at both sintering temperatures. The exhibition of the dielectric https://www.sciencedirect.com/topics/materials-science/permittivity dispersion is ascribed to the Maxwell–Wagner interfacial polarization. At 1050 °C, the x = 0.05 composite exhibits giant dielectric constant which is attributed to the increased density. AC conductivity study ascertains that the conduction mechanism is mainly accounted for the small polaron hopping. Complex impedance and electric modulus studies ascertain the non-Debye type relaxation mechanism. The permeability increases up to certain proportion of NCBCTO and deteriorates with further increase in NCBCTO content at both sintering temperatures. The increment is accounted for the improved grain size and density while the decrement is attributed to the magnetic dilution caused by the excess amount of NCBCTO. The Q-factor increases up to certain proportion of NCBCTO and decreases with further increase in NCBCTO. The increment in Q-factor is a consequence of the reduced resistivity at the grain boundaries while the deterioration is ascribed to the increased resistivity. Therefore, it can be said that addition of proper concentration of NCBCTO to NCZFO can prove the electromagnetic properties.