Magnetodynamic Properties of Rare-Earth-Doped Permalloy Nanowires

We investigated the effect of rare-earth (RE) element doping on magnetodynamic properties of 1D Ni ₈₀ Fe ₂₀ (Py) nanowires. 5% of doping of RE element (La, Nd, and Sm) in Py nanowires was successfully done by electrodeposition technique in porous anodic alumina template. It is observed by the X-ray diffraction (XRD) measurements that the crystal structure of Py nanowires decreases from polycrystalline to amorphous phase with doping of RE element. The magnetic properties demonstrated that the saturation magnetization decreases upto 98% with the higher atomic number RE dopant. The ferromagnetic resonance measurements in field-sweep mode were done to analyze the magnetization dynamics of RE-doped nanowires. The fitting of resonance field and field linewidth was done by using the Landau-Lifshitz-Gilbert equation. It is observed that the resonance field increases with Sm doping as compared to La doping. The damping constants have been achieved by decocting the extrinsic linewidth and found to increase by ~12 times with RE doping. The increase of Gilbert damping emanates from the enhancement of L-S coupling in Py nanowires.