Structural and temperature-dependent magnetic characteristics of Ho doped CoFe 2 O 4 nanostructures

The magnetism in low-dimensional materials is the consequence of several factors, including the type of crystal structure and spatial distribution of nanoparticles. Understanding and exploring these challenges are vital to introduce nanomaterials for industrial applications. The present study reveals the substitutional effect of Holmium on the magnetic properties of cobalt ferrite. The nanostructures are prepared by co-precipitation procedure for the stoichiometric growth of CoHo x Fe 2-x O 4 (0 ≤ x  ≤ 0.1); Δ x  = 0.025 ferrite compositions. The crystal structure and phase determination of all the samples identify a typical cubic structure (Fd-3m); however, a secondary phase, appearing at x = 0.1, originates due to the formation of HoFeO 3. An increasing trend in lattice constant, X-ray density and hopping lengths with Ho doping in Co ferrite is observed in the synthesized nanoparticles. The structural analysis by high-resolution transmission electron microscopy confirms the crystal structure of spinel ferrite. The magnetic characteristics measured at room temperature depict that the coercivity, saturation magnetization, and magneton number increase due to the impact of Ho 3+ substitution. The saturation magnetization of CoHo 0.05 Fe 1.95 O 4 nanoparticles as a function of temperature satisfies Bloch's law, and the coercivity of the sample remained in good agreement with Kneller's law.