Synthesis and magnetic properties of Fe_0.32Ni_0.68 alloy nanotubes

Fe_0.32Ni_0.68 alloy nanotubes have been successfully synthesized by electrochemical deposition using a polycarbonate membrane template. The transmission electron microscope and scanning electron microscope observations reveal that the nanotubes have a conical morphology with two ends stuffed and a hollow structure. The length and diameter of the nanotubes are 7-8 νm and 200 nm, respectively. The aspect ratio (length to diameter) is as large as 40. Magnetic measurements show that the coercivities of the nanotubes for an applied parallel and perpendicular field are about 21 and 55 Oe, respectively. The hysteresis loops indicate that the nanotubes were more easily magnetized in applied parallel field than in applied perpendicular field. The mechanism of nucleation and growth of these nanotubes is also discussed.