Synthesis and characterization of Co-based magnetic nanowires

Pure Co, pure Cu and Co/Cu two-segment nanowires with high pore filling rate and uniform sizes were successfully synthesized through the direct electrochemical deposition in Anodic Aluminum Oxide (AAO) membrane. By applying different deposition currents in a single mix bath, nanowires with different materials and different crystal structure were fabricated. The length of the nanowires is several micron and diameter is between 80-100 nm. The pure Co nanowires and the Co segment in the Co/Cu nanowires show hexagonal close packed (hcp) crystal structure. The pure Cu nanowires and the Cu segments in Co/Cu nanowires show face centered cubic (fcc) structure. Magnetic force microscopy (MFM) analysis illustrates the quasi-periodic magnetization modulation along the pure Co wires and the Co segment in Co/Cu two-segment nanowires. A pair of Co/Cu two-segment nanowires partially in contact showed magnetization interactions at the Co segments. The magnetization modulation is explained by the competition between shape anisotropy and magnetocrystalline anisotropy.