AC magnetic susceptibility and heat dissipation of Zn-doped Mg-ferrite nanoparticles

•Mg1-xZnxFe2O4 with ×  = 0.2 exhibited the highest magnetization by doping Zn ions into the A-site of the spinel structure.•・The coercivity of all samples was nearly zero, suggesting superparamagnetic behavior.•・The analysis of the frequency-dependence of AC susceptibility showed that the system follows the Debye relaxation.•・The temperature-increase of the sample with ×  = 0.2 and 18 nm was sufficient to kill cancer cells even under low frequencies and magnetic fields.•・In vitro experiment, we confirmed that hyperthermia suppressed 25% of the cancer cells in 30 min using 18 nm particles.