CoxFe100−x and CoxFe95−xCu5, with 30 < x < 90, arrays of nanowire, around 20 nm in diameter and about 5 μm long, have been prepared by electrodeposition filling the self-assembled nanopores of anodic alumina templates. These samples were later thermally annealed for 2 h in the range of temperatures up to 600 °C. Crystalline anisotropy was confirmed to exhibit bcc cubic structure with  texture in as-prepared state. First structural changes are observed after annealing at 450 °C when a refinement of such cubic phase is observed. Annealing at higher temperatures promotes the appearance of Co and Fe oxides. Small addition of Cu to CoFe alloys induces only limited variations in the magnetic properties for as-prepared samples. Nevertheless, the presence of small Cu content promotes a significant magnetic hardening in comparison with the effect observed in CoFe nanowires. From the temperature dependence of magnetic properties in as-prepared and annealed samples we conclude a complex contribution of various anisotropy energy terms coming from the annealing and from the presence of Cu.
The presence of Cu in small amount induces significant changes in the magnetic properties of annealed CoFeCu nanowires.