Structural and magnetic properties of Ho-doped CuFe2O4 nanoparticles prepared by a simple co-precipitation method

Abstract

Nanocrystalline copper (II) ferrite with a spinel structure doped with holmium was synthesized by co-precipitation using an aqueous solution of NaOH as a precipitant and subsequent annealing at 800°C for 60 min. The doping limit was determined by X-ray phase analysis. The similarity of the real and nominal compositions of the doped samples was established by energy-dispersive X-ray spectroscopy using a scanning electron microscope. The obtained particles had an approximately spherical shape, and their size was 40-70 nm (X-ray phase analysis, transmission electron microscopy). The introduction of Ho3+ cations to χ = 0.15 into a CuFe2O4 spinel lattice led to a decrease in the average size of crystallites, an increase in the coercive force of nanopowders, and a decrease in excess magnetization and saturation magnetization. Synthesized CuFe2-xHoxO4 (χ = 0, 0.1 and 0.15) nanopowders were magnetically hard materials with high coercive force.