Forward volume and surface magnetostatic modes in an yttrium iron garnet film for out-of-plane magnetic fields: Theory and experiment

Jinho Lim,John B Ketterson,Dovran Amanov,Wonbae Bang,Jonathan Trossman

doi:10.1063/1.5007263

Jinho Lim, John B Ketterson + Show 3 more

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https://doi.org/10.1063/1.5007263

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Journal: AIP Advances	Publication Date: Dec 28, 2017
Citations: 7	License type: cc-by

Affiliation: Northwestern University, University of Hong Kong

Abstract

We present experimental and theoretical results on the propagation of magnetostatic spin waves in a film of yttrium iron garnet (YIG) for out-of-plane magnetic fields for which propagation in opposite directions is nonreciprocal in the presence of a metal layer. The plane studied is defined by the film normal n and n × k where k is the wave vector of the mode. Spin waves in this setting are classified as forward volume waves or surface waves and display non-reciprocity in the presence of an adjacent metal layer except for when H//n. The measurements are carried out in a transmission geometry, and a microwave mixer is used to measure the change of phase, and with it the evolution of wavevector, of the arriving spin wave with external magnetic field.

Highlights

Long wavelength spin waves are magnetostatic in character and can be divided into two catagories: i) those where the static magnetic field, H, is parallel to the yttrium iron garnet (YIG) surface and ii) those where it has a non-vanishing perpendicular component
We have developed a theory for the propagation magnetostatic waves in the presence of a metal layer when static magnetic field lies in FV-DE plane
The yttrium iron garnet (YIG) film used in these experiments was grown epitaxially on a gadolinium gallium garnet (GGG) substrate and had a thickness is 9.72 μm

Summary

INTRODUCTION

Long wavelength spin waves are magnetostatic in character and can be divided into two catagories: i) those where the static magnetic field, H, is parallel to the YIG surface (an in-plane geometry) and ii) those where it has a non-vanishing perpendicular component (an out-of-plane geometry). In the absence of a metal layer there is an exact solution in the magnetostatic limit for the DE1 and FV2 geometries, but not for intermediate angles. There have been studies of the non-reciprocity of the surface mode in the presence of a metal layer in the DE geometry,[3,4,5,6] but not at intermediate angles for FV-DE plane. We have developed a theory for the propagation magnetostatic waves in the presence of a metal layer when static magnetic field lies in FV-DE plane. We have compared the experimental and theoretical results and used them to determine an effective spacing between YIG film and metal (Cu) layer

THEORY

EXPERIMENT

CONCLUSION