Magnetic Investigation of Se/In Codoped Co_0.5Ni_0.5Fe₂O₄ Spinel Nanoparticles Synthesized via the Sonochemical Route

The magnetic traits of sonochemically synthesized Co_0.5Ni_0.5In_xSe_3xFe_2-5xO₄ nanoparticles [(In/Se → Co_0.5Ni_0.5Fe₂O₄) (x ≤ 0.1) NPs] have been investigated in detail. X-ray powder diffraction analysis confirmed the purity and cubic phase crystalline structure of all products. The products’ chemical composition has been confirmed by EDX and elemental mapping analyses. The magnetization characteristics of Co_0.5Ni_0.5In_2xSe_3xFe_2-6xO₄ (In/Se → Co_0.5Ni_0.5Fe₂O₄) (x ≤ 0.1) NPs revealed superparamagnetic behavior at room temperature and ferrimagnetic behavior at low temperatures (T_s). The blocking temperature (T_B) that defines the superparamagnetic-ferrimagnetic state transition was also determined via analysis of the ZFC and FC magnetization curves. T_B was found to move to lower T_s as the amount of selenium amount increased. Moreover, the undoped Co_0.5Ni_0.5Fe₂O₄ NPs displayed the highest magnetic characteristics (such as M_s, M_r, H_c, K_eff, and n_B), which are depressed after In/Se codoping. The superparamagnetic feature could be promising for some interesting applications, including biosensing, magnetic hyperthermia, magnetic resonance imaging, and targeted drug delivery, while the ferrimagnetic behavior can make the material interesting for electrical applications.