Role of magnetic anisotropy on the hyperthermia efficiency of spherical Fe_3-xCo_xO₄ (x = 0 – 1) nanoparticles

Alternating current (AC) hyperthermia therapy using magnetic nanoparticles has shown potential to replace or supplement well-established cancer treatments, such as radiotherapy and chemotherapy that have severe side effects. The majority of magnetic hyperthermia is to create nanomaterials with improved heating efficiency and long blood circulation time. In this study, we demonstrate a simple strategy to enhance the heating efficiency of Fe₃O₄ nanoparticles through substitution of Fe⁺² ions with Co⁺² ions. Magnetic and hyperthermia experiments on the 7 nm Fe_3-xCo_xO₄ (x = 0 – 1) nanoparticles showed that the Blocking temperature (T_B), the coercive field (H_C) at 10 K, and the specific absorption rate (SAR) followed a similar trend with a maximum at x = 0.75, which is in corroboration with the theoretical prediction. Our study revealed that the heating efficiency of the Fe_3-xCo_xO₄ nanoparticles not only depends on the saturation magnetization and size but also on their magnetocrystalline anisotropy.