Study of spin dynamics and damping on the magnetic nanowire arrays with various nanowire widths

TL;DR

This study explores how nanowire width affects spin dynamics and damping in ferromagnetic nanowire arrays, combining experimental VNA-FMR measurements with micromagnetic simulations to reveal width-dependent damping behavior.

Contribution

It provides a detailed analysis of the relationship between nanowire width and Gilbert damping, supported by experimental and simulation data, which is a novel insight in magnetic nanowire research.

Findings

Damping constant increases with nanowire width in transverse fields.

Excellent agreement between VNA-FMR measurements and micromagnetic simulations.

Demagnetization factors vary with nanowire width and magnetic field orientation.

Abstract

We investigate the spin dynamics including Gilbert damping in the ferromagnetic nanowire arrays. We have measured the ferromagnetic resonance of ferromagnetic nanowire arrays using vector-network analyzer ferromagnetic resonance (VNA-FMR) and analyzed the results with the micromagnetic simulations. We find excellent agreement between the experimental VNA-FMR spectra and micromagnetic simulations result for various applied magnetic fields. We find that the demagnetization factor for longitudinal conditions, Nz (Ny) increases (decreases) as decreasing the nanowire width in the micromagnetic simulations. For the transverse magnetic field, Nz (Ny) increases (decreases) as increasing the nanowire width. We also find that the Gilbert damping constant increases from 0.018 to 0.051 as the increasing nanowire width for the transverse case, while it is almost constant as 0.021 for the longitudinal case.