Nanoscale X-ray imaging of spin dynamics in yttrium iron garnet

J Förster,E Josten,J Raabe,D A Bozhko,S Wintz,J Gräfe,N Träger,G Schütz,A N Slavin,C Dubs,J Bailey,G Dieterle,M Weigand,H Stoll,S Finizio

doi:10.1063/1.5121013

Abstract

Time-resolved scanning transmission x-ray microscopy has been used for the direct imaging of spin-wave dynamics in a thin film yttrium iron garnet (YIG) with sub-200 nm spatial resolution. Application of this x-ray transmission technique to single-crystalline garnet films was achieved by extracting a lamella (13×5×0.185 μm3) of the liquid phase epitaxy grown YIG thin film out of a gadolinium gallium garnet substrate. Spin waves in the sample were measured along the Damon-Eshbach and backward volume directions of propagation at gigahertz frequencies and with wavelengths in a range between 200 nm and 10 μm. The results were compared to theoretical models. Here, the widely used approximate dispersion equation for dipole-exchange spin waves proved to be insufficient for describing the observed Damon-Eshbach type modes. For achieving an accurate description, we made use of the full analytical theory taking mode-hybridization effects into account.

Highlights

Spin waves are collective magnetic excitations in ferro, ferri, and antiferromagnetic materials and an active research area in the field of magnetism
We present Time-resolved scanning transmission x-ray microscopy (TR-STXM) measurements in yttrium iron garnet (YIG), which provide a new view on the rich and complex scenario of the spin-wave characteristics, their interactions, and coexistence in the nanometer range of this pivotal model system for design and understanding of future magnonic/spintronic applications
Spin waves of wavelengths down to 200 nm have been directly imaged in YIG using TR-STXM

Summary

Introduction

Spin waves are collective magnetic excitations in ferro-, ferri-, and antiferromagnetic materials and an active research area in the field of magnetism. Besides the fundamental impact of this topic, there has been increasing interest in potential applications of spin waves as information carriers. This has led to the emergence of the field of magnonics. Spin waves excellently cover the Gigahertz-regime of frequencies, which is common in today’s communications devices, allowing their creation and detection via well-developed scitation.org/journal/jap microwave techniques. Spin waves are actively discussed as high-speed and short-wavelength information carriers for novel spintronic/magnonic devices, in particular with respect to quantum effects and computing at low temperatures.

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Conclusion