Incoherent Nuclear Resonant Scattering from a Standing Spin Wave

Jakob Gollwitzer,Guido Meier,Ralf Röhlsberger,Marcus Herlitschke,Christian F Adolff,Olaf Leupold,Hans Christian Wille,Kai Schlage,Lars Bocklage

doi:10.1038/s41598-018-29596-z

Abstract

We introduce a method to study the spatial profiles of standing spin waves in ferromagnetic microstructures. The method relies on Nuclear Resonant Scattering of 57Fe using a microfocused beam of synchrotron radiation, the transverse coherence length of which is smaller than the length scale of lateral variations in the magnetization dynamics. Using this experimental method, the nuclear resonant scattering signal due to a confined spin wave is determined on the basis of an incoherent superposition model. From the fits of the Nuclear Resonant Scattering time spectra, the precessional amplitude profile across the stripe predicted by an analytical model is reconstructed. Our results pave the way for studying non-homogeneous dynamic spin configurations in microstructured magnetic systems using nuclear resonant scattering of synchrotron light.

Highlights

NRS involves a linearly polarized beam of 14.4 keV synchrotron radiation energy scattering from the energy levels of 57Fe nuclei
We demonstrate the importance of the transverse coherence length (TCL) in interpreting nuclear resonant scattering data from laterally varying dynamic spin configurations
The microfocused beam used in this study has a TCL that is orders of magnitude smaller than the lateral length scale of variations of the dynamic spin structure of the standing spin wave

Summary

Introduction

NRS involves a linearly polarized beam of 14.4 keV synchrotron radiation energy scattering from the energy levels of 57Fe nuclei. Film excited in the Kittel mode at GHz frequencies[10] We expand these studies to show that NRS is capable of reconstructing the dynamic magnetization profile of spinwaves in laterally confined microstructures. Important to this end is the fact that coherence properties of the beam influence the nuclear resonant scattering process from a system with lateral variation in the response to the synchrotron pulse. NRS can be used to probe laterally varying spin structures which opens new avenues in using NRS to study dynamic spin configurations in microstructured magnetic systems It highlights that control of the transverse coherence length is a prerequisite for accurate NRS data interpretation obtained from systems with laterally varying magnetizations

Methods

Results

Conclusion