Title : Structure, electrical and magnetic properties of Cu-Ni substituted cobalt ferrite nanoparticles CuXCo0.8-XNi0.2Fe2O4 synthesized by sol-gel autocombustion process
Abstract:
In this study, the five Cu-Ni substituted cobalt ferrite nanoparticles: Co0.8Ni0.2Fe2O4; Cu0.2Co0.6Ni0.2Fe2O4; Cu0.4Co0.4Ni0.2Fe2O4; Cu0.6Co0.2Ni0.2Fe2O4 and Cu0.8Ni0.2Fe2O4, have been prepared using eco-friendly sol gel autocombustion process. The physicochemical characterization results derived from Fourier transform infrared (FTIR), X-ray powder diffraction (XRPD), field emission scanning electron microscopy (FESEM), differential thermal analysis (DTA) and thermogravimetric analysis (TGA), have confirmed that the ferrite synthesized powders are pure and are formed by homogeneous crystallites having a size varying from 19.96 nm to 24.94 nm. In addition, the nanosized ferrite cubic spinel basic framework has an excellent stability versus copper substitution and thermal treatment beyond the combustion temperature and without any detection of tetragonal-cubic phase transition. Furthermore, the zero-field-cooled (ZFC)-field-cooled (FC) and the magnetization versus magnetic field strength measurements using superconducting quantum interface device (M-H SQUID) magnetometry have proved the presence of superparamagnetic behavior at room temperature. Also, the superparamagnetic parameter theoretical calculations have been performed by using Langevin function fitting on M-H(300 K) data and the results indicate their remarkable dependence on crystallite size and copper composition impact. Indeed, during the substitution process a decrease has been observed in remanence, saturation magnetization, coercivity, blocking temperature and magnetocrystalline values. The complex impedance spectroscopy (CIS) study has highlighted the best electrical conductivity value 18.07x10-3 S.cm-1 associated to the lowest Ea = 0.360 eV of Ni0.2Cu0.8Fe2O4 at 373 K. The excellent magnetic and electrical features of the synthesized nanosized Cu-Ni substituted cobalt ferrites enable them to be useful for various nanotechnological applications in the precious fields of modern life.
