Negative-energy spin waves in antiferromagnets for spin-current amplification and analogue gravity

Fuente: arXiv
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Main Authors: Errani, Valentina, Schoenmaker, Steven H., Wang, Xiangrong R., Gomonay, Olena, Duine, Rembert A.
Format: Preprint
Published: 2024
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_version_ 1866929337734791168
author Errani, Valentina
Schoenmaker, Steven H.
Wang, Xiangrong R.
Gomonay, Olena
Duine, Rembert A.
author_facet Errani, Valentina
Schoenmaker, Steven H.
Wang, Xiangrong R.
Gomonay, Olena
Duine, Rembert A.
contents Magnonic black holes-analogue event horizons for the spin-wave collective excitations of ordered magnets-can be used for fundamental research, for example for investigating Hawking radiation, but also for technological applications of spin waves. Here we show how to engineer a horizon for spin waves in antiferromagnets, which have the attractive feature of fast magnetization dynamics and linear dispersion relation. We propose a set-up with spatially varying exchange interaction with spin transfer torque to implement the horizon and a second set-up for the amplification of spin waves consisting of an antiferromagnet subject to a spatially varying external magnetic field that is driven by spin orbit torque. We compute the values of parameters needed to implement the horizon and to have amplification of spin waves. We develop the corresponding Klein-Gordon equation and quantify the amplification. Our work paves the way for investigation of Hawking radiation of spin waves and for antiferromagnet-based spin-waves amplifiers.
format Preprint
id arxiv_https___arxiv_org_abs_2405_04996
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Negative-energy spin waves in antiferromagnets for spin-current amplification and analogue gravity
Errani, Valentina
Schoenmaker, Steven H.
Wang, Xiangrong R.
Gomonay, Olena
Duine, Rembert A.
Mesoscale and Nanoscale Physics
Magnonic black holes-analogue event horizons for the spin-wave collective excitations of ordered magnets-can be used for fundamental research, for example for investigating Hawking radiation, but also for technological applications of spin waves. Here we show how to engineer a horizon for spin waves in antiferromagnets, which have the attractive feature of fast magnetization dynamics and linear dispersion relation. We propose a set-up with spatially varying exchange interaction with spin transfer torque to implement the horizon and a second set-up for the amplification of spin waves consisting of an antiferromagnet subject to a spatially varying external magnetic field that is driven by spin orbit torque. We compute the values of parameters needed to implement the horizon and to have amplification of spin waves. We develop the corresponding Klein-Gordon equation and quantify the amplification. Our work paves the way for investigation of Hawking radiation of spin waves and for antiferromagnet-based spin-waves amplifiers.
title Negative-energy spin waves in antiferromagnets for spin-current amplification and analogue gravity
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2405.04996