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.

Template Assisted Deposition of Ferromagnetic Nanostructures: from Antidot Thin Films to Multisegmented Nanowires

“…For that purpose, a sequential approach that combines anodization, pore enlargement by isotropic chemical etching of PW steps and ALD functionalization, was employed [21]. Two samples (G1 and G2) have been prepared by following this process.…”

Potential Controlled Co-Ni Nanowires with Compositional Gradient

“…High versatility of nanostructures is due their physical properties, high surface to area ratio, and electronic properties [1][2][3][4][5][6].…”

“…Nanowires (NWs) with good magnetic properties and electrical conductivity are obtained from Co-Ni alloys [2][3][4][5][6][7][8][9][10][11][12]. However, the control of the NW composition is challenging in the iron group alloys due to the anomalous deposition [9, 10, 12-14], which presents an obstacle to the straightforward codeposition of Co-Ni alloys.…”

“…Generally speaking, to control the composition of Co-Ni nanowires, the deposition may be performed in a single electrolyte containing Co and Ni ions [1,2,8,9,11,12,[15][16][17][18][19][20][21]. Another way to control the deposition, which is less common, is to perform the deposition in alternating electrolytes containing either Co or Ni [4,6,22].…”

“…Another way to control the deposition, which is less common, is to perform the deposition in alternating electrolytes containing either Co or Ni [4,6,22]. Unlike the deposition in two electrolytes, the deposition in a single electrolyte results in an alloy whose composition can be modified by adjusting the electrolyte concentration [1,2,8,9,11,12,[15][16][17][18][19][20][21]. This method allows for a better control of the composition by managing the deposition protocol (i.e.…”