Magneto-optical properties and magnetic inductive heating of sodium oleate coated Fe3O4 magnetic fluid

The Fe3O4 nanoparticles coated by sodium oleate (SO) were prepared by chemical co-precipitation method. Via Stokes polarimeter, the retardance of water-based SO coated Fe3O4 magnetic fluids (MFs with a mass ratio of 50% as SO to Fe3O4) with 1 g/ml is measured as 2.86° (dichroism is 0.064) under 64.5 mT. Next, the heating performance of SO coated MFs in the alternating magnetic field was investigated and the potential in the magnetic fluid hyperthermia was evaluated. According to TEM, the diameter distribution for the SO coated MF (mass ratio of 50%) is within 10–25 nm. When the concentrations of SO coated MFs are of 2 mg/ml and 50 mg/ml, under the external alternating magnetic field with applied apparent current of 210 A, after heating 200 s, the temperature of the coated MFs is greater than 45 °C, respectively, reached the requirements for the magnetic inductive heating treatment of medicinal cancer tumor.