Synthesis and investigation of structural, elastic, and electrical properties of cobalt and magnesium substituted Ni–Zn spinel ferrite nanoparticles

Abstract

The sol-gel auto-combustion approach was used to create Ni0.4M0.2Zn0.4Fe2O4 (M=Ni2+, Mg2+, and Co2+) nanoparticles. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDS), and an inductance-capacitance-resistance (LCR) meter were used to analyse the samples’ structural, elastic, and electrical properties. In all samples, the XRD patterns obtained indicated the formation of a monophasic cubic spinel structure with no identifiable impurity phase, which was supported by EDS investigations. The introduction of substituting ions, specifically Mg2+ and Co2+, into Ni-Zn ferrite nanoparticles results in an increase in the lattice parameter. The lattice parameter for Ni-Zn is 8.377Ao, while for the substituted nanoparticles it is 8.389 and 8.388 Ao for Mg2+ and Co2+ respectively. Additionally, the crystallite size of the substituted nanoparticles increases to 46.57 nm from 40.75 nm for Ni-Zn. However, the X-ray density of the substituted nanoparticles decreases to 5.180 and 5.337 g/cm3 for Mg2+ and Co2+ respectively, from 5.358 g/cm3 for Ni-Zn. The elastic parameters, such as the Young's modulus, Debye temperature, bulk modulus, and rigidity modulus, were calculated. The good elastic characteristics of Ni-Zn ferrite were confirmed and may be explained by the lower lattice parameter values and smaller crystallite sizes. Temperature and frequency effects on dielectric behaviour and AC electrical conductivity (σAC) were investigated. At ambient temperature, the dielectric characteristics, specifically the dielectric constant (ε') and loss tangent (tanδ), were computed over a frequency range of 100 Hz to 2 MHz. The compositions display normal dielectric properties, which are attributed to the interfacial polarisation following the Maxwell-Wagner model. The AC conductivity of nanoparticles was shown to decrease when Mg2+ and Co2+ were substituted into Ni-Zn ferrite. Furthermore, the AC conductivity diminishes with decreasing frequency, which is a sign of ionic conductivity. There was a direct relationship between the temperature and the values of ε', tanδ, and σAC for different ions.