Templated fabrication and characterization of SiO2 nanotube covered Fe nanowires

Abstract

In this study, Fe nanowires coated with SiO2 nanotubes have been synthesized by electrodeposition method using anodic alumina oxide template. Before growing Fe nanowires, 6–8 nm 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 SiO2 insulated Fe nanowires inside the membrane are characterized by superconducting quantum interference device. Coercivities of around 120 Oe with field parallel to the nanowire axis and 240 Oe 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.