Upcoming Webinar
We invite you to join a virtual meeting of the Action on:
Friday, February 28, at 14:15 CET
Speaker: Mathias Kläui, Johannes Gutenberg University of Mainz
Title: Topological Spin Structures - from 2D phase transitions to unconventional computing.
Abstract:
Novel spintronic devices can play a role in the quest for GreenIT if they are stable and can transport and manipulate spin with low power.
Devices have been proposed, where switching by energy-efficient approaches is used to manipulate topological spin structures such as skyrmions [1]. Beyond the comparably simple skyrmions, we find novel topological spin structures, such as bi-merons that can be stabilized in synthetic antiferromagnets [2].
We combine ultimate stability of topological states due to chiral interactions [3,4] with ultra-efficient manipulation using novel spin torques [3-5]. In particular orbital torques [6] increase the switching efficiency by more than a factor 10.
We use skyrmion dynamics for non-conventional stochastic computing applications, where we developed skyrmion reshuffler devices [7] based on skyrmion diffusion, which also reveals the origin of skyrmion pinning [8]. Such diffusion can furthermore be used for Token-based Brownian Computing and Reservoir Computing [9].
A particularly exciting property of such spin structures in their ordering that can comprise topological phase transitions proposed by Kosterlitz and Thouless and observed in skyrmion ensembles [10].
References:
1. G. Finocchio et al., J. Phys. D: Appl. Phys., vol. 49, no. 42, 423001, 2016; K. Everschor-Sitte et al., J. Appl. Phys., vol. 124, no.
24, 240901, 2018.
2. M. Bhukta et al., Nature Commun. vol. 15, pp. 1641, 2024.
3. S. Woo et al., Nature Mater., vol. 15, no. 5, pp. 501–506, 2016.
4. K. Litzius et al., Nature Phys., vol. 13, no. 2, pp. 170–175, 2017.
5. K. Litzius et al., Nature Electron., vol. 3, no. 1, pp. 30–36, 2020.
6. S. Ding et al. Phys. Rev. Lett. 125, 177201, 2020; Phys. Rev. Lett.
128, 067201, 2022.
7. J. Zázvorka et al., Nature Nanotechnol., vol. 14, no. 7, pp. 658–661, 2019; 8. R. Gruber et al., Nature Commun. vol. 13, pp. 3144, 2022.
9. K. Raab et al., Nature Commun. vol. 13, pp. 6982, 2022; G. Beneke et al., Nature Commun. vol. 15, pp. 8103, 2024.
10. M. Kläui, Nature Nanotechnol. 15, 726, 2020; R. Gruber et al.,
arxiv:2501.13151
Following the seminar, we will discuss recent updates and planned activities for the Action.
To ensure smooth participation, please set your Zoom display name to include your full name and institution for identification purposes.
We look forward to your participation on February 28.