Rare earth Ho³⁺-substituted Co–Ni ferrites having a chemical formula Co_0.6Ni_0.4Fe_2−xHo_xO₄ (0.0, 0.025, 0.05, 0.075, and 0.1) were prepared via sol-gel route. The phase formation of these samples was confirmed by the thermogravimetric analysis with differential thermal analysis and X-ray powder diffraction techniques. Rietveld refinement confirms the cubic spinel structure of the prepared samples having space group Fd3− m with presence of secondary phase of α-Fe₂O₃. The lattice parameter is increased from 8.412 to 8.582 Å with Ho³⁺ ion concentration in cobalt–nickel ferrite from x = 0 to x = 0.1. The distribution of cations has been studied with the help of X-ray diffraction data and it is found that Ho³⁺ ions preferred to occupy the octahedral [B] site. The other structural parameters like X-ray density, bulk density, hopping length, and allied parameter are increased with the composition of Ho³⁺ ions in the Co–Ni ferrite. The morphology of the samples was observed by transmission electron microscopy and scanning electron microscopy showed the nanostructured formation.

通过溶胶-凝胶法制备化学式为Co _0.6 Ni _0.4 Fe _2-x Ho _x O ₄（0.0、0.025、0.05、0.075和0.1）的稀土元素Ho ³⁺取代的Co-Ni铁氧体。这些样品的相形成通过差示热分析和X射线粉末衍射技术的热重分析来确认。Rietveld修正确认具有的α-Fe的第二相的存在空间群Fd3-米所制备的样品的立方尖晶石结构₂ ö ₃。晶格参数从8.412增加至8.582埃与何³⁺离子浓度在钴-镍铁素体从X = 0至x  = 0.1。借助X射线衍射数据研究了阳离子的分布，发现Ho ³⁺离子优选占据八面体[B]位。其他结构参数（例如X射线密度，堆积密度，跳变长度和相关参数）会随着Co-Ni铁氧体中Ho ³⁺离子的组成而增加。通过透射电子显微镜观察样品的形态，并且扫描电子显微镜显示纳米结构的形成。