Fabrication and magnetic properties of Co70Cu30 alloy nanowire arrays with high coercivity

CoCu solid solution alloy nanowire arrays which exhibit the face-centered cubic structure with strong [220] orientation along the nanowire axes are fabricated for first time in the anodic aluminum oxide template by electrodeposition. The proportion of Co ingredient in CoCu alloy nanowire arrays is up to 70%. Transmission electron microscopy revealts that the nanowire arrays are uniform and continuous and have a large aspect ratio of about 300. The magnetic hysteresis loop demonstrates that the Co70Cu30 alloy nanowire arrays have a large coercivity of about 2438 Oe and relatively large squareness of about 0.76 parallel to nanowire arrays which greatly exceeds the value previousely reported. Good magnetic properties are achieved due mainly to the larger proportion of Co ingredient than that in the normal CoCu alloy nanowire arrays and the large shape anisotropy. The results of magnetic measurement and the calculations from formula demonstrate that the symmetric fanning mechanism of sphere chains model could be employed to explain the magnetization reversal process which is related to the structure of the Co70Cu30 nanowire arrays.