Annealing and morphology effects on the Fe0.39Co0.61 nanowire arrays

Highly ordered arrays of parallel Fe0.39Co0.61 alloy nanowires with diameter around 50 nm and length several micrometers were prepared by electrodeposition of Fe2+ and Co2+ into the porous anodic aluminum oxide (PAO) templates. The deposition was performed in an aqueous solution of Fe2+ and Co2+ sulfates. The structure and magnetic properties were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM), respectively. Nanowires and nanotubes were found in the as-prepared samples. Such nanowire arrays were in bcc structure and had excellent perpendicular anisotropy with their easy axis parallel to nanowire arrays. Annealing can improve the coercivity of nanowire arrays. Coercivity as high as 2700 Oe was obtained in the samples annealing at 500 °C. The annealing and morphology effects were also discussed in detail. MFM results showed that each nanowire was a single-domain structure. The recording density was expected to be up to 50 Gbits/in.2 if one single domain represented one bit of information, which is very promising in high-density recording.