Fabrication and Magnetic Properties of MnFe2O4 Nanowire Arrays

One of the most important magnetic materials, ferrite nanoparticles, has extensively been studied because of their potential applications in magnetic storage media and magnetic resonance imaging (MRI). The magnetic properties of these nanoparticles can significantly change depending on their shape. 8 nm manganese ferrite nanoparticles were synthesized by thermal decomposing the metal complex and surfactant. The process of embedding MnFe2O4 nanoparticles into the pores of the anodic aluminum oxide (AAO) was assisted by the magnetic field of the permanent magnet that was placed directly under the substrate in the vacuum. The nanowires formed in the pores from the ferrite nanoparticles were annealed at 400 degrees C and 600 degrees C in an Ar gas atmosphere in order for the morphology to transform. The morphology of the manganese ferrite nanoparticles before and after annealing was observed using a field-emission scanning electron microscope. The coercivity and squareness of the hysteresis loop of the annealed ferrite that resulted from the morphological changes increased when the annealing temperature increased.