Effect of Yb doping on the structural and magnetic properties of cobalt ferrite nanoparticles

Abstract The low coercivity of spinel ferrites is a significant barrier limiting their use in high-density magnetic recording applications. The large magnitude of the magnetocrystalline anisotropy of the rare earth group elements can lead to a high coercivity field by doping the magnetic ferrites with these elements. In this research, using the hydrothermal method, Fe+3 in cobalt ferrite was substituted with Yb+3 to make CoFe2-xYbxO4 with x=0, 0.025, 0.05, 0.075, and 0.1. By analyzing the X-ray diffraction analysis and confirming the spinel structure, the crystallite sizes were obtained in the range of 31 nm to 45 nm. The lattice parameter was estimated to be in the range of 8.30 nm to 8.36 nm. The FTIR analysis of the nanoparticles showed the ν1 absorption band in the range 584 Cm−1 to 594 Cm−1. The Raman spectroscopy analysis showed that CoFe2-xYbxO4 nanoparticles have a mixed spinel structure. Hysteresis loops at room temperature and 10 K obtained by the vibrating sample magnetometer (VSM) indicate that the coercivity field (HC) increases significantly from 0.55 to 1.05 KOe and 9.48 to 12.00 KOe, respectively, by increasing Yb doping from x=0 to x=0.1.