Enhanced hyperthermia performance in hard-soft magnetic mixed Zn_0.5Co_xFe_2.5-xO₄/SiO₂ composite magnetic nanoparticles

High quality Zn_0.5Co_xFe_2.5-xO₄ (x = 0, 0.05, 0.1, 0.15) serial magnetic nanoparticles with single cubic structures were prepared by the modified thermal decomposition method, and Zn_0.5Co_xFe_2.5-xO₄/SiO₂ composite magnetic nanoparticles were prepared by surface modification of SiO₂. The magnetic anisotropy of the sample increases with the increase of the doping amount of Co²⁺. When the doping amount is 0.1, the sample shows the transition from superparamagnetism to ferrimagnetism at room temperature. In the Zn_0.5Co_xFe_2.5-xO₄/SiO₂ serial samples, the maximum value of specific loss power (SLP) with 1974 W/g _metal can also be found at doping amount of x = 0.1. The composite nanoparticles are expected to be an excellent candidate for clinical magnetic hyperthermia.