Template‐assisted Co–Ni alloys and multisegmented nanowires with tuned magnetic anisotropy

Abstract

Homogeneous Co85Ni15 and Co54Ni46 alloys, together multisegmented Co85Ni15/Co54Ni46 magnetic nanowire arrays have been synthesized by means of potentiostatic and pulsed potentiostatic electrodeposition techniques, respectively, into the pores of hard‐anodic alumina templates. Morphological, compositional and structural characterization indicate that the composition of Co–Ni alloy segments and nanowires can be properly adjusted by varying the electrochemical deposition potential, leading to different crystalline structures (fcc or hcp) depending on the Co–Ni alloy composition. The magnetic properties of homogeneous and multisegmented Co–Ni alloy nanowire arrays, obtained from hysteresis loops and switching field distribution calculations, are correlated with their crystalline structure and effective magnetic anisotropy, to shed light on the magnetization processes that determine the magnetic behaviour of the nanowire arrays. Part (a) shows a schematic drawing of freestanding multisegmented Co85Ni15/Co54Ni46 nanowires. Part (b) displays the magnetic hysteresis loops of multisegmented nanowire arrays measured along the parallel and perpendicular directions with respect to the nanowires long axis.