Emission and Propagation of Multi-Dimensional Spin Waves with nanoscale wavelengths in Anisotropic Spin Textures

TL;DR

This paper demonstrates the generation and guidance of nanoscale spin waves in anisotropic magnetic bilayers, showing potential for magnonic waveguides in future spin-based computing and signal processing.

Contribution

It provides experimental evidence of controlling spin wave propagation along domain walls with nanoscale wavelengths in anisotropic ferromagnetic bilayers, a novel approach for magnonic devices.

Findings

Spin waves with wavelengths from 150 nm to 1 μm were generated and propagated.

Propagation distances exceeded multiple wavelengths, demonstrating effective guidance.

Spin waves were observed at frequencies from 250 MHz to 3 GHz.

Abstract

Spin waves offer intriguing novel perspectives for computing and signal processing, since their damping can be lower than the Ohmic losses in conventional CMOS circuits. For controlling the spatial extent and propagation of spin waves on the actual chip, magnetic domain walls show considerable potential as magnonic waveguides. However, low-loss guidance of spin waves with nanoscale wavelengths, in particular around angled tracks, remains to be shown. Here we experimentally demonstrate that such advanced control of propagating spin waves can be obtained using natural features of magnetic order in an interlayer exchange-coupled, anisotropic ferromagnetic bilayer. Using Scanning Transmission X-Ray Microscopy, we image generation of spin waves and their propagation across distances exceeding multiple times the wavelength, in extended planar geometries as well as along one-dimensional domain walls, which can be straight and curved. The observed range of wavelengths is between 1 {\mu}m and 150 nm, at corresponding excitation frequencies from 250 MHz to 3 GHz. Our results show routes towards practical implementation of magnonic waveguides employing domain walls in future spin wave logic and computational circuits.