Magnetization dynamics of weak stripe domains in Fe-N thin films: a multi-technique complementary approach

TL;DR

This study investigates the complex magnetization eigenmodes in nitrogen-implanted Fe-N thin films with stripe domains using multiple experimental techniques and simulations, revealing rich mode spectra and their evolution under magnetic fields.

Contribution

It introduces a multi-technique approach combining Brillouin light scattering, ferromagnetic resonance, and micromagnetic simulations to analyze localized magnetic excitations in stripe domain structures.

Findings

Rich spectrum of eigenmodes detected with different techniques

Mode frequencies and profiles evolve with external magnetic field

Complementary techniques reveal localized magnetic excitations

Abstract

The resonant eigenmodes of a nitrogen-implanted iron {\alpha}'-FeN characterized by weak stripe domains are investigated by Brillouin light scattering and broadband ferromagnetic resonance experiments, assisted by micromagnetic simulations. The spectrum of the dynamic eigenmodes in the presence of the weak stripes is very rich and two different families of modes can be selectively detected using different techniques or different experimental configurations. Attention is paid to the evolution of the mode frequencies and spatial profiles under the application of an external magnetic field, of variable intensity, in the direction parallel or transverse to the stripes. The different evolution of the modes with the external magnetic field is accompanied by a distinctive spatial localization in specific regions, such as the closure domains at the surface of the stripes and the bulk domains localized in the inner part of the stripes. The complementarity of BLS and FMR techniques, based on different selection rules, is found to be a fruitful tool for the study of the wealth of localized mag-netic excitations generally found in nanostructures.