Dynamic control of spin-wave propagation

Jan-Niklas Toedt,Wolfgang Hansen

doi:10.1038/s41598-021-86887-8

Abstract

In this work we present a method to dynamically control the propagation of spin-wave packets. By altering an external magnetic field the refraction of the spin wave at a temporal inhomogeneity is enabled. Since the inhomogeneity is spatially invariant, the spin-wave impulse remains conserved while the frequency is shifted. We demonstrate the stopping and rebound of a traveling Backward-Volume type spin-wave packet.

Highlights

In this work we present a method to dynamically control the propagation of spin-wave packets
Apart from some exceptions, such investigations were limited to statically defined systems, e.g. redirecting spin waves in spatially heterogeneous but statically defined magnetization p atterns[9,10], disregarding the capability to dynamically alter the spin-wave properties in the timescale of spin-wave propagation
We propose the expansion of the concept to remotely steer spin-wave packets by rotating the external magnetic field

Summary

Introduction

In this work we present a method to dynamically control the propagation of spin-wave packets. Spin waves offer an outstanding external controllability of their properties due to the dependence on strength and orientation of externally applied magnetic fields. In this work we discuss the redirection of running spin-wave packets via refraction at a temporal change of the medium, i.e., by altering an externally applied magnetic field while the spin wave packet propagates. If we consider a Backward-Volume wave packet generated at an external field of μ0H0 = 16 mT with a central frequency of fc = 4 GHz the central wave number will be kc = 15.8 μm−1 , according to the dispersion relation. If spatial heterogeneities of the medium or magnetic field occur (e.g. at the borders of a magnetic film) the wave-vector composition of the wave packet will be altered

Methods

Results

Conclusion