Abstract
•A new series of nanoferrites composed of Ni1-xHoxFe2O4 (0 ≤ x ≤ 0.07) were prepared.•The preparation was carried out via 1,4-Dithioerythritol assisted polyol technique.•The Ho dopant caused an enhancement of the magnetic properties.•The magnetic constants increase by 5 times compared to undoped ferrites.•These ferrites can be used as catalysis or magnetic nanocarriers for drug delivery.
A new family of nanoferrites composed of Ni1-xHoxFe2O4 (0 ≤ x ≤ 0.07) was developed via a 1,4-dithioerythritol assisted polyol technique. The influence of holmium (Ho) cations on the lattice constant, nanoparticle size, and stoichiometry of the cubic spinel structures were examined using X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). Doping with Ho cations (up to 3 wt%) in Ni1-xHoxFe2O4 causes an increase of the nanocrystal diameter and the lattice constant. The FTIR and Raman measurements showed the migration of iron cations from tetrahedral to octahedral sublattices due to incorporation of Ho cations. Magnetic (M-H) measurements demonstrated that Ni0.97Ho0.03Fe2O4 exhibits a remarkable improvement of the coercive field (129.7 Gauss) and the saturation magnetization (36.6 emu/g) compared with NiFe2O4, for which the coercive field is 23.3 Gauss and the saturation magnetization is 7.5 emu/g. The enhancement of magnetic constants by more than five orders of magnitude for Ni1-xHoxFe2O4 nano-ceramics make them promising as magnetic catalytic materials and magnetic nanocarriers for drug delivery applications.