Facile synthesis of PVA-MnFe2O4 nanocomposite : Its magnetic investigation

• Manganese ferrite (MnFe2O4)-polyvinyl alcohol (PVA) nanocomposite was prepared by a PVA assisted sot-gel auto-combustion method. The magnetic core of the carriers was manganese ferrite (MnFe2O4), with average crystallite size of 9.1 +/- 2.1 nm. The PVA-MnFe2O4 nanocomposite exhibited superparamagnetic behavior at room temperature and ferromagnetic behavior at low temperatures. Zero-field-cooled and field-cooled measurements further confirm the superparamagnetic behavior with a blocking temperature of 160 K. The lower reduced remanent magnetization values than theoretical value of 0.5 indicate that the PVA/MnFe2O4 nanocomposite used in this study has uniaxial anisotropy rather than the expected cubic anisotropy according to the Stoner-Wohlfarth model. The calculated magnetic anisotropy constant of the sample is similar to 1.45 x 10(6) erg/cm(3) which is significantly higher than that of the bulk MnFe2O4 due to the strong magnetic coupling between magnetic core and surface spins.

Nyckelord

Magnetic materials

Nanostructures

Sol-gel chemistry

Impedance spectroscopy

Magnetic properties

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