Role of cerium dopant in tuning the semiconductor-to-metal transition properties of magnesium zinc ferrite nanomaterials

Abstract

In this research work, Magnesium zinc ferrite (Ce_xMgZn_1-xFe₂O₄) nanomaterials have been synthesized with various cerium concentrations (x = 0, 0.05, 0.1, 0.15) using the coprecipitation method. With no deformation as per structural analysis, cerium ions are doped in the spinel lattice of MgZnFe₂O₄ nanomaterials. The undoped MgZnFe₂O₄ with initial flake-like morphology is changed to cube-like shapes upon Ce (x = 0.15) addition. The DC resistivity exhibits a varying pattern in both ferromagnetic and paramagnetic regions as temperature increases. Furthermore, the samples with x = 0.15 exhibit a high resistivity on the order of 1.09∗10¹⁰ Ω cm, and an activation energy of 0.909 eV. The dielectric properties, such as dielectric constant, dielectric losses, and impedance, exhibit a progressive drop as the frequency increases from 1 MHz to 2 MHz. Furthermore, dielectric parameters reach their lowest value in the dopant x = 0.1. The highest Q values for x = 0.05 and 0.15 indicate that the mentioned materials are most suitable for use in high-frequency devices, likewise multi-layer chip inductors and resonant circuits. Growth inhibition of two types of bacterial extracts (E.Coli and S. aureus) has been studied. Results revealed MgZnFe₂O₄ enhanced growth inhibition against S. aureus bacteria with increasing Ce concentration, however, inhibition of E. Coli is hampered (50 % at maximum) by Ce incorporation into ferrite lattice.