Co-precipitation synthesis of (Zn-Mn)-co-doped magnetite nanoparticles and their application in magnetic hyperthermia

In this work, a series of zinc- and manganese-co-doped magnetite nanoparticles was synthesized by co-precipitation method and their magnetization and magnetic hyperthermia properties were evaluated according to the degree of doping. The syntheses of the magnetic nanoparticles were carried out in the presence of polyethyleneglycol (PEG) at 353 K using aqueous medium. Several samples was synthesized with nominal composition of (Zn_xMn_1-xFe_0.6)Fe₂O₄, x = (0–0.4). All samples were characterized by XRD and pure spinel structure like was observed, having about 13 nm diameter and truncated octahedral morphology. The magnetometry measures showed that the Zn and/or Mn additions in the magnetite structure contributed to enhance of the saturation magnetization as expected with the highest value of saturation magnetization for Zn-Mn equivalent doped magnetite. The magnetic hyperthermia properties were evaluated in aqueous media at pH 5 for 10 min in a 25 mT and 112 kHz alternating magnetic field and it was observed that manganese-only doped sample reached the highest hyperthermia rate, while Zn doping decreased hyperthermia property. The intrinsic loss power (ILP) values varies from 0.2 to 1.0 nHm² kg⁻¹ with Mn doping values increasing and the magnetic hyperthermia effect was assigned mainly to the Néel-Brownian relaxation process.