Templated fabrication and characterization of SiO₂ nanotube covered Fe nanowires

In this study, Fe nanowires coated with SiO₂ nanotubes have been synthesized by electrodeposition method using anodic alumina oxide template. Before growing Fe nanowires, 6-8nm thick SiO₂ nanotubes are grown inside the template using a "surface sol-gel" technique. The nanotube structures were characterized by field emission scanning electron microscopy and energy dispersive x-ray spectroscopy. Magnetic properties of the SiO ₂ insulated Fe nanowires inside the membrane are characterized by superconducting quantum interference device. Coercivities of around 120Oe with field parallel to the nanowire axis and 240Oe with field perpendicular the nanowire axis are observed at room temperature. These values are comparable to Fe nanowires without insulating layer in membrane. The magnetic hysteresis loop suggests that the SiO₂ insulated nanowires have uniaxial magnetic anisotropy with the easy axis magnetization direction along the nanowire arrays due to their large shape anisotropy.