Accelerated ultrafast demagnetization of an interlayer-exchange-coupled Co/Mn/Co trilayer

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Main Authors: Gördes, Jendrik, Kumberg, Ivar, Awsaf, Chowdhury S., Walter, Marcel, Shinwari, Tauqir, Thakur, Sangeeta, Sharma, Sangeeta, Schüßler-Langeheine, Christian, Pontius, Niko, Kuch, Wolfgang
Format: Preprint
Published: 2025
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author Gördes, Jendrik
Kumberg, Ivar
Awsaf, Chowdhury S.
Walter, Marcel
Shinwari, Tauqir
Thakur, Sangeeta
Sharma, Sangeeta
Schüßler-Langeheine, Christian
Pontius, Niko
Kuch, Wolfgang
author_facet Gördes, Jendrik
Kumberg, Ivar
Awsaf, Chowdhury S.
Walter, Marcel
Shinwari, Tauqir
Thakur, Sangeeta
Sharma, Sangeeta
Schüßler-Langeheine, Christian
Pontius, Niko
Kuch, Wolfgang
contents We investigate the ultrafast magnetization dynamics of an interlayer-exchange-coupled Co/Mn/Co trilayer system after excitation with an ultrafast optical pump. We probe element- and time-resolved ferromagnetic order by X-ray magnetic circular dichroism in resonant reflectivity. We observe an accelerated Co demagnetization time in the case of weak total parallel interlayer coupling at 9.5 ML Mn thickness for antiparallel alignment of both Co layers compared to parallel alignment as well as for parallel alignment in the case of strong parallel interlayer coupling at 11 ML of Mn. From ab initio time-dependent density functional theory calculations, we conclude that optically induced intersite spin transfer of spin-polarized electrons from Co into Mn acts as a decay channel to enhance and accelerate ultrafast demagnetization. This spin transfer can only take place in case of a collinear Mn spin structure. We argue that this is the case for antiparallel alignment of both Co layers at 9.5 ML Mn thickness and parallel alignment in case of 11 ML of Mn. Our results point out that an antiferromagnetic spacer layer and its spin structure have a significant effect on the magnetization dynamics of adjacent ferromagnetic layers. Our findings provide further insight into fundamental mechanisms of ultrafast demagnetization and may lead to improve dynamics in multilayered systems for faster optical switching of magnetic order.
format Preprint
id arxiv_https___arxiv_org_abs_2505_24547
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Accelerated ultrafast demagnetization of an interlayer-exchange-coupled Co/Mn/Co trilayer
Gördes, Jendrik
Kumberg, Ivar
Awsaf, Chowdhury S.
Walter, Marcel
Shinwari, Tauqir
Thakur, Sangeeta
Sharma, Sangeeta
Schüßler-Langeheine, Christian
Pontius, Niko
Kuch, Wolfgang
Materials Science
We investigate the ultrafast magnetization dynamics of an interlayer-exchange-coupled Co/Mn/Co trilayer system after excitation with an ultrafast optical pump. We probe element- and time-resolved ferromagnetic order by X-ray magnetic circular dichroism in resonant reflectivity. We observe an accelerated Co demagnetization time in the case of weak total parallel interlayer coupling at 9.5 ML Mn thickness for antiparallel alignment of both Co layers compared to parallel alignment as well as for parallel alignment in the case of strong parallel interlayer coupling at 11 ML of Mn. From ab initio time-dependent density functional theory calculations, we conclude that optically induced intersite spin transfer of spin-polarized electrons from Co into Mn acts as a decay channel to enhance and accelerate ultrafast demagnetization. This spin transfer can only take place in case of a collinear Mn spin structure. We argue that this is the case for antiparallel alignment of both Co layers at 9.5 ML Mn thickness and parallel alignment in case of 11 ML of Mn. Our results point out that an antiferromagnetic spacer layer and its spin structure have a significant effect on the magnetization dynamics of adjacent ferromagnetic layers. Our findings provide further insight into fundamental mechanisms of ultrafast demagnetization and may lead to improve dynamics in multilayered systems for faster optical switching of magnetic order.
title Accelerated ultrafast demagnetization of an interlayer-exchange-coupled Co/Mn/Co trilayer
topic Materials Science
url https://arxiv.org/abs/2505.24547