Improved magnetic and electrical properties of transition metal doped nickel spinel ferrite nanoparticles for prospective applications

Abstract

Mn2+ and Cr3+ co-doped nickel ferrite nanoparticles are synthesized via cost effective and eco-friendly chemical co-precipitation method. The work reports sequentially the influence of dopants on the structural, electrical and magnetic properties of nickel ferrite for potential applications. The inverse spinel structure with face centered cubic structure is confirmed using X-ray diffraction analysis. The lattice constants increased because of larger size of metal ions as compared to that of iron ions. The crystallite size calculated using Sherer formula from XRD pattern are in the range of 17–31 nm. The morphology of doped samples changed slightly as confirmed from scanning electron microscopy (SEM). The parameters like dielectric constant, dielectric loss, alternating current conduction and impedance show normal behavior of ferrite in the range of 1 MHz–3 GHz. The dielectric constant (3.01), dielectric loss (0.09) and alternating current conduction (0.80 × 10−2 Ω−1 cm−1) of co-doped nickel ferrite exhibited lower values at dopant content of x,y = 0.2 and then starts to increase while the impedance showed reverse trend. The magnetic measurements showed enhanced saturation magnetization (24.5 emu/g) and decrease in coercivity up to 30.3 Oe with changing dopants concentration. The x, y = 0.1, and 0.2 composition exhibited optimum values of dielectric constant, dielectric loss, alternating current conduction and coercivity while high values of electrical impedance and saturation magnetization. Therefore, the synthesized material with nominal composition Ni0.9Mn0.1Fe1.9Cr0.1O4 and Ni0.8Mn0.2Fe1.8Cr0.2O4 can be successfully used for applications in magnetic devices, microwave frequency devices and transformer cores.