Electroplating and magnetostructural characterization of multisegmented Co(54)Ni(46)/Co(85)Ni(15) nanowires from single electrochemical bath in anodic alumina templates

Highly hexagonally ordered hard anodic aluminum oxide membranes, which have been modified by a thin cover layer of SiO(2) deposited by atomic layer deposition method, were used as templates for the synthesis of electrodeposited magnetic Co-Ni nanowire arrays having diameters of around 180 to 200 nm and made of tens of segments with alternating compositions of Co(54)Ni(46) and Co(85)Ni(15). Each Co-Ni single segment has a mean length of around 290 nm for the Co(54)Ni(46) alloy, whereas the length of the Co(85)Ni(15) segments was around 430 nm. The composition and crystalline structure of each Co-Ni nanowire segment were determined by transmission electron microscopy and selected area electron diffraction techniques. The employed single-bath electrochemical nanowire growth method allows for tuning both the composition and crystalline structure of each individual Co-Ni segment. The room temperature magnetic behavior of the multisegmented Co-Ni nanowire arrays is also studied and correlated with their structural and morphological properties.