Optimized microstructure and magnetic properties in arrays of ac electrodeposited Co nanowires induced by the continuous and pulse electrodeposition

Cobalt nanowire arrays were fabricated by ac (continuous and pulse) electrodeposition into anodic aluminium oxide templates. The effects of continuous electrodeposition waveform and frequency as well as the pulse feature on the structure and magnetic properties of the nanowire arrays were studied. For continuous electrodeposition into the low depth nanohole, the microstructures and magnetic properties of the Co nanowires are independent of the waveform and frequency due to relatively rapid electrodeposition growth. The hcp Co nanowires with high crystallinity were fabricated using the pulse technique. More than 50 ms off-time between the pulses induces the preferentially growth direction of Co nanowires (the c-axis parallel to the wire axis), thereby improving the magnetic properties. A coercive force of 2370 Oe was obtained for Co nanowires fabricated with a pulse of 100 ms off-time and 5 ms reductive/oxidative time.