Fabrication and magnetic properties of CoNi alloy nanotube arrays

CoNi nanotubes were prepared in pores of anodic aluminum oxide templates via a dc electrodeposition method. The dependence of product morphology on the applied potential was studied over the range −1.0 to −2.5 V. The results showed that a critical potential related to the electrodeposition parameters exists, below which the deposited product was almost entirely in the form of nanotubes, whereas above which, nanowires are formed. Magnetic measurements showed hysteresis loops of the nanotubes are discontinuous. Theoretical analysis suggested the existence of some peculiar magnetization configuration such as vertical Bloch line which was responsible for the discontinuity of the hysteresis loops.