Electromagnetic approach to cavity spintronics

Macêdo, R. , Holland, R. C., Baity, P. G. , McLellan, L. J., Livesey, K. L., Stamps, R. L. , Weides, M. P. and Bozhko, D. A. (2021) Electromagnetic approach to cavity spintronics. Physical Review Applied, 15(2), 024065. (doi: 10.1103/PhysRevApplied.15.024065)

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234863.pdf - Accepted Version



The fields of cavity quantum electrodynamics and magnetism have recently merged into cavity spintronics, investigating a quasiparticle that emerges from the strong coupling between standing electromagnetic waves confined in a microwave cavity resonator and the quanta of spin waves, magnons. This phenomenon is now expected to be employed in a variety of devices for applications ranging from quantum communication to dark matter detection. To be successful, most of these applications require a vast control of the coupling strength, resulting in intensive efforts to understanding coupling by a variety of different approaches. Here, the electromagnetic properties of both resonator and magnetic samples are investigated to provide a comprehensive understanding of the coupling between these two systems. Because the coupling is a consequence of the excitation vector fields, which directly interact with magnetization dynamics, a highly accurate electromagnetic perturbation theory is employed that predicts the resonant hybrid mode frequencies for any field configuration within the cavity resonator. The coupling is shown to be strongly dependent not only on the excitation vector fields and sample’s magnetic properties but also on the sample’s shape. These findings are illustrated by applying the theoretical framework to two distinct experiments: a magnetic sphere placed in a three-dimensional resonator and a rectangular, magnetic prism placed in a two-dimensional resonator. The theory provides comprehensive understanding of the overall behavior of strongly coupled systems and it can be easily modified for a variety of other systems.

Item Type:Articles
Additional Information:This work is supported by the European Research Council (ERC) under Grant No. 648011, the Initiative and Networking Fund of the Helmholtz Association, the Leverhulme Trust, and the University of Glasgow through LKAS funds. D.A B. acknowledges support from the Alexander von Humboldt Foundation. R.H. is supported by the Engineering and Physical Sciences Research Council (EPSRC) through the Vacation Internships Scheme.
Glasgow Author(s) Enlighten ID:Stamps, Professor Robert and McLellan, Dr Luke and Weides, Professor Martin and Bozhko, Dr Dmytro and Holland, Mr Rory and Baity, Dr Paul and Macedo, Dr Rair
Authors: Macêdo, R., Holland, R. C., Baity, P. G., McLellan, L. J., Livesey, K. L., Stamps, R. L., Weides, M. P., and Bozhko, D. A.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
College of Science and Engineering > School of Physics and Astronomy
Journal Name:Physical Review Applied
Publisher:American Physical Society
ISSN (Online):2331-7019
Published Online:25 February 2021
Copyright Holders:Copyright © 2021 American Physical Society
First Published:First published in Physical Review Applied 15(2): 024065
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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