Magnetic Properties of Uniform Nanowire arrays

Fabrication and magnetic measurements of ferromagnetic (Ni and Co) nanowire arrays using nanochannel glass templates are presented. These nanowire arrays have novel characteristics: The nanowires are very parallel (to within a fraction of a degree) and regularly placed. They are circular with extremely uniform diameter (of less than 80 nm for some samples) both along individual wire's length and among different wires within an array. Magnetic measurements show enhanced coercivities compared to the bulk values. The saturation magnetization for Ni nanowires depends much more strongly on temperature than that for Co nanowires. The coercivities are also dependent strongly on temperature and can be explained by a thermal-activation model.