Effects of dipolar interactions on the magnetic hyperthermia of Zn_0.3Fe_2.7O ₄ nanoparticles with different sizes

Tumor-targeted magnetic hyperthermia has recently attracted much attention. Magnetic nanoparticles (NPs) are heat mediator nanoprobes in magnetic hyperthermia for cancer treatment. In this paper, single cubic spinel structural Zn_0.3Fe_2.7O₄ magnetic NPs with sizes of 14 nm-20 nm were synthesized, followed by coating with SiO₂ shell. The SLP value of Zn_0.3Fe_2.7O₄/SiO₂ NPs below 20 nm changes non-monotonically with the concentration of solution under the alternating current (AC) magnetic field of 430 kHz and 27 kA/m. SLP values of all Zn_0.3Fe_2.7O₄/SiO₂ NPs appear a peak value with change of solution concentration. The solution concentrations with optimal SLP value decrease with increasing magnetic core size. This work can give guidance to the better prediction and control of the magnetic hyperthermia performance of materials in clinical applications.