Synthesis, structural, morphological, electrical and magnetic properties of (1-x) [Ni0.35Cu0.15Zn0.50Mn0.05Fe1.95O4] + (x) [Rice husk ash] composites

Abstract Polycrystalline (1-x) [Ni0.35Cu0.15Zn0.50Mn0.05Fe1.95O4] (NCZMFO) + (x) [Rice husk ash] (RHA) (where x = 0.00, 0.05, 0.10, 0.20, 0.30, 0.50 and 0.70) were synthesized by the conventional solid state sintering route. X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectra confirmed the coexistence of NCZMFO and RHA phases in the composites. At higher RHA content, FTIR bands of NCZMFO ferrite were suppressed, and some bands overlapped with the SiO2 bands. The density and microstructures revealed that density and grain growth rate strongly depend on the RHA content. Dielectric properties are well consistent with the Maxwell-Wagner interfacial polarization. The presence of single semicircular arcs in Nyquist plots signifies that conduction is due to the grain interior only. The magnetization decreases with RHA content. The permeability deteriorates as the RHA content increases because Si4+ and Ca2+ are segregated to the grain boundaries which impede the domain wall motion and presence of pores.