Investigation of structural, elastic and magnetic properties of Cu2+ ions substituted cobalt nano ferrites

Thakur, A., Verma, R., Wan, F., (...), Ovchinnikov, S., Thakur, P.// Journal of Magnetism and Magnetic Materials//

https://doi.org/10.1016/j.jmmm.2023.170980

In the present work, we synthesized the Cu-doped CoFe₂O₄ (Co_1-xCu_xFe₂O₄) nanoparticles with × = 0.0, 0.2, 0.4 and 0.6, by employing the citrate precursor method. The X-ray Diffraction (XRD) pattern confirmed the pure cubic structure formation with the Fd-3m space group. To know the structural purity of each sample as well as the distribution of cations, Rietveld refinement was carried out. The crystallite size increases from 39.55 nm to 41.80 nm upto x = 0.2 and with further doping of Cu²⁺ ions it decreases to 36.27 nm. Similar variation is observed in the lattice parameter where the value of ‘ $a$ ’ first increases from 8.378 Å to 8.381 Å and then decreases to 8.377 Å. The development of a non-uniform grain is seen using scanning electron microscope (SEM), which reveals the reduction in grain size. Fourier Transform Infrared Spectroscopy (FTIR) showed the two peaks $v_{1}$ and $v_{2}$ for all the samples around 541 cm⁻¹ and 408 cm⁻¹, respectively, which further decreases to 532.5 cm⁻¹ and 402.5 cm⁻¹ as the dopant ion concentration increases. The Stiffness constant, and Elastic modulus decrease with doping whereas, the Poisson’s ratio and Pugh’s ratio show a constant value of around 0.249 and 1.660, respectively. Vibrating Sample Magnetometer (VSM) analysis shows a decrease in saturation magnetization ( $σ_{s}$ ) value from 76.85 emu/g to 43.62 emu/g. The net magnetic moment ( $n_{B}$ ) decreases from 3.29 $μ_{B}$ to 1.85 $μ_{B}$ and the effective anisotropy constant value decreases from 10.672erg/g to 4.461erg/g. Thus, the prepared nanoparticles provide a way forward for their industrial applications.