Impact of Co-doped NiFe2O4 (CoxNi1−xFe2O4) nanostructures prepared by co-precipitation route on the structural, morphological, surface, and magnetic properties

Abstract

The excellent magnetic properties of spinel ferrite-based materials are preferably utilized in magnetic storage devices, and recording media. The magnetic properties of cobalt-doped nickel ferrite (Cox Ni1-xFe2O4) nanoparticles (NPs) were successfully investigated. A series of cobalt (Co)-doped nickel ferrite Cox Ni1-xFe2O4 NPs (x = 0.6, 0.7, 0.8, 0.9,1.0) were synthesized by the sol-gel method auto-combustion (SGAC) route. The crystallite sizes of the prepared CoxNi1−xFe2O4 NPs were found to be 23.5 ± 0.4, 25.3 ± 0.3, 25.0 ± 0.6, 29.5 ± 0.3, and 12.7 ± 0.3 nm for x = 0.6, 0.7, 0.8, 0.9, and 1.0, respectively, using X-ray diffraction (XRD) patterns. The random-shaped morphology with particle sizes was found to be 16.4 ± 0.8, 12.6 ± 0.1, 15.4 ± 0.7, 12.5 ± 0.2, and 11.9 ± 0.4 nm for CoxNi1−xFe2O4 (x = 0.6, 0.7, 0.8, 0.9, and 1.0), respectively, using high-resolution transmission electron microscopy (HRTEM). Tauc’s plot spectra of CoxNi1−xFe2O4 NPs showed that the direct band (2.01–2.42 eV) and indirect band gaps (0.86–1.16 eV) were tuned with Co2+ concentrations. The obtained binding energies (BEs) observed at (780–801 eV) for Co2+ and Co3+ions, (855–879 eV) for Ni2+ and Ni3+ ions, (710–760 eV) for Fe3+ and Fe2+ ions, and (529–531 eV) for O2- ions, respectively in CoxNi1−xFe2O4 NPs were confirmed by X-ray photoelectron spectroscopy (XPS). RT-dependent DC magnetization measurements exhibited saturation magnetization (45.28, 37.34, 33.32, 33.93, and 52.57 emu/g), coercivity (1090, 1160, 689, 507, and 377 Oe), retentivity (13.29, 12.86, 11.37, 8.10, and 10.18 emu/g), and magnetic anisotropy (4.834 ×106, 4.315 ×106, 4.037 ×106, 4.206 ×106, and 7.578 ×106 erg/cm3) for CoxNi1-xFe2O4 NPs (x = 0.6, 0.7, 0.8, 0.9, and 1.0), respectively. The improved magneto-crystalline anisotropy and decreased spin canting effect/ spin disorder for CoxNi1−xFe2O4 NPs indicated that the current research work can be suitable for magnetic storage devices and recording media.