Investigation of easy axis transition and magnetodynamics in Ni76Fe24 nanowires and Ni77Fe23 nanotubes synthesized by DC electrodeposition

- The Ni76Fe24 nanowires and Ni77Fe23 nanotubes are formed using DC electrodeposition.
- Magnetization reversal (MR) mechanism occurs by nucleation mode in Ni76Fe24 nanowires.
- MR occurs by combination of curling and nucleation in Ni77Fe23 nanotubes.
- Ferromagnetic relaxation mechanism in nanomaterials is explained using LLG equation.
- The thermal energy decreases at low temperature causing an increase in magnetization.

Well rounded, smooth and elegantly elongated Ni76Fe24 nanowires and Ni77Fe23 nanotubes were successfully fabricated inside the home made anodized aluminum oxide (AAO) templates at room temperature by cost effective DC electrodeposition. In order to explore surface information and atomic percentage, samples were characterized by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) respectively. It is observed that highly homogeneous and uniform nanowires with Length = 10 μm and diameter = 50 nm and nanotubes with Length = 8 μm and diameter = 50 nm are formed. Different magnetic parameters i.e. M-H curves, coercivity (Hc), saturation magnetization (Ms) and magnetization reversal mode were also investigated by vibrating sample magnetometer (VSM). It is observed from angular dependence of coercivity that magnetization reversal mechanism occurs by nucleation mode in Ni76Fe24 nanowires and combination of curling and nucleation in Ni77Fe23 nanotubes. Different magnetic interactions were ruled out with the help of delta M curves. It is found that dipole-dipole interactions dominate over shape anisotropy due to which the easy axis entirely re-oriented towards the perpendicular from the wire and tube axis. Furthermore this fact of easy axis transition was also confirmed by Ferromagnetic resonance (FMR) performed at frequency f = 9.8 GHz by sweeping magnetic field from parallel to perpendicular of nanocylinder axis. The ferromagnetic relaxation mechanism is explained on the basis spin-orbit interaction and s-d interaction mechanism using LLG equation. The MH loops of Ni77Fe23 nanotubes at low temperature confirms that thermal energy decreases at low temperature causing an increase in saturation magnetization. This study will be useful for the application of nanocylinders in various Spintronics devices.