Magnetic properties of electrodeposited nanowires

Abstract

Electrodeposited multilayered nanowires grown within a polycarbonate membrane constitute a new medium in which giant magnetoresistance (GMR) perpendicular to the plane of the multilayers can be measured. These structures can exhibit a perpendicular GMR of at least 22% at ambient temperature. We performed detailed studies both of reversible magnetization and of irreversible remanent magnetization curves for CoNiCu/Cu/CoNiCu multilayered and CoNiCu pulse-deposited nanowire systems with Co:Ni ratios of 6:4 and 7:3 respectively in the range 10 - 290 K, allowing the magnetic phases of these structures to be identified. Shape anisotropy in the pulse-deposited nanowire and inter-layer coupling in the multilayered nanowire are shown to make important contributions to the magnetic properties. Dipolar-like interactions are found to predominate in both nanowire systems. Magnetic force microscope (MFM) images of individual multilayered nanowires exhibit a contrast consistent with there being a soft magnetization parallel to the layers. Switching of the magnetic layers in the multilayered structure into the direction of the MFM tip's stray field is observed.

Magnetic Interaction in FeCo Alloy Nanotube Array

“…From irreversible susceptibility curves, we can get the switching fields distribution (SFD). In general terms a broad SFD is indicative of wide variation in the micromagnetic environment within the magnetic material [20]. It can be seen from Fig.…”

“…Henkel Plot and ΔM plot are widely used to study the interactions between the nanoscale materials [17,20,22,23]. Here, ΔM plot is employed to study the magnetic interaction in FeCo alloy nanotube array.…”

Synthesis of High Coercivity Cobalt Nanotubes with Acetate Precursors and Elucidation of the Mechanism of Growth

“…4,9,10,15 There are also reports where nanotubes and nanowires have been synthesized by using highly sophisticated techniques such as pulse laser deposition or molecular beam epitaxy. 16,17 Ferromagnetic nanotubes based on Ni, Fe, and Co are being investigated in great detail due to their application potential in diverse fields such as perpendicular magnetic recording, cell separation, diagnosis, therapeutics, and magnetic resonance imaging for detection. The ease with which they can be functionalized by using a specific group is an added advantage of these nanostructures and can be used for drug targeting and other applications in biotechnology.…”

Structure and magnetization of arrays of electrodeposited Co wires in anodic alumina

“…The disadvantage of these techniques is that they are expensive and it is time consuming to write nanostructures on large scales, although recently 1 optical interference techniques are being developed to circumvent this problem. Another way to fabricate large scale periodic nanostructures is by electrodeposition of magnetic materials in the pores of nuclear track etched polycarbonate membranes [2][3][4][5][6] or in the pores of self-ordered nanochannel material formed by anodization of Al in an acid solution, [7][8][9][10] a low cost and fast technique to produce large arrays of identical magnetic entities, with a very large aspect ratio ͑length divided by diameter͒, which is not possible with standard lithographic techniques. Wires in anodic alumina have the advantage above wires in polycarbonate membranes in that they are completely parallel and exactly perpendicular to the membrane surface and, moreover, the wires are assumed to have a constant diameter 11 throughout their entire length.…”