Synthesis of high coercivity core-shell nanorods based on nickel and cobalt and their magnetic properties

Abstract

Hybrid magnetic nanostructures with high coercivity have immense application potential in various fields. Nickel (Ni) electrodeposited inside Cobalt (Co) nanotubes (a new system named Ni @ Co nanorods) were fabricated using a two-step potentiostatic electrodeposition method. Ni @ Co nanorods were crystalline, and they have an average diameter of 150 nm and length of ~15 μm. The X-ray diffraction studies revealed the existence of two separate phases corresponding to Ni and Co. Ni @ Co nanorods exhibited a very high longitudinal coercivity. The general mobility-assisted growth mechanism proposed for the growth of one-dimensional nanostructures inside nano porous alumina during potentiostatic electrodeposition is found to be valid in this case too.

Keywords: Core–shell nanostructures; Hybrid nanostructures; Magnetic nanowires; Mobility-assisted growth mechanism; Nanorods.

Figure 1

Schematic diagram showing the synthesis of Ni @ Co nanorods

Figure 2

a TEM image of Co NT, b TEM image of Ni NW (inset: ED of Ni NW), c FESEM image of Ni @ Co nanorods, and d TEM image of Ni @ Co nanorod, after removing the alumina membrane

Figure 3

EDS of Ni @ Co nanorods

Figure 4

XRD pattern of Ni @ Co nanorods

Figure 5

M(H) curves of Ni @ Co nanorods; a at room temperature b at 6 K