INFLUENCE OF SATURATION MAGNETIZATION AND VISCOSITY ON SPECIFIC LOSS POWER FOR CoFe2O4 AND MnFe2O4 MAGNETIC NANOPARTICLES

Magnetic nanoparticles absorb energy from external alternating magnetic field to create ananosized heating source. Specific loss power (SLP) is affected strongly by several magneticparameters of material and viscosity of nanofluid. In this study, the specific loss power asdependent on saturation magnetization was calculated for hard ferrite CoFe2O4 (K = 290 kJ/m3)and soft ferrite MnFe2O4 (K = 3 kJ/m3) with two values of viscosity in biological range 1-2 mPas.Besides, we investigated the experimental dependence SLP on their saturation magnetizationwhile changing viscosity using agar powder. A large change of slopesSLPMwas found for CFOwhen the viscosity changes; whereas it remained almost unaffected by the variation of viscosityfluid of MFO. All calculation and experimental results are discussed via the competitionbetween Néel and Brown relaxation.

Heating of Zn-Substituted Manganese Ferrite Magnetic Nanoparticles in Alternating Magnetic Field

In this report, were studied the heating capability of magnetic nanoparticles (MNps) made from Zn-substituted manganese ferrite compounds ZnxMn1-xFe2O4 with Zn content varying from 0% to 90%. The MNps of diameter 5-25 nm were synthesized by co-precipitation of metal salt solution with NaOH solution. It was shown, that specific absorption rate (SAR) for the compound with Zn content of 20% is bigger than the other ones exhibited 1.5 W/g. Also SAR for the magnetic liquids made of the MNps shows bigger SAR values, which indicates the Brown relaxation mechanism in the system.