Curie temperature and magnetic permeability regulation of Cr–Mg co-doped NiCuZn ferrite for tumor hyperthermia

The controllable Curie temperature and high magnetic permeability of NiCuZn ferrites make them promising candidates for magnetic thermal medium. However, the temperature control of existing NiCuZn ferrite materials is not accurate enough to achieve the low Curie temperature required for tumor hyperthermia. In order to further achieve the desired Curie temperature and facilitate the advancement of temperature control materials for tumor hyperthermia, Cr–Mg co-doped NiCuZn ferrite was studied. The study investigated the influence of varying concentrations of Cr 3+ on the crystal structure and magnetic properties of Mg–NiCuZn ferrites. The results of structural characterization demonstrate that Cr–Mg co-doped NiCuZn ferrites exhibit high density and uniform distribution of elements. The introduction of Cr 3+ leads to a reduction in lattice parameters and a preference for octahedral B-sites. The hysteresis loop results show that the saturation magnetization first increases and then decreases with the increase of Cr 3+ concentration. Ni 0.09 Mg 0.20 Cu 0.14 Zn 0.60 Fe 1.89 Cr 0.050 O 3.94 ferrite at 0.30 wt% of Bi 2 O 3 exhibits optimal magnetic characteristics, including a saturation magnetization of ∼36.7 emu/g, low coercivity of ∼0.07 kA/m, high permeability of ∼982.43 @1 MHz, and an appropriate Curie temperature of 45.59 °C. Such permeability and Curie temperature can be used in the body cavity perfusion hyperthermia and deep thermal therapy.