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We present a novel method for generating spin currents using the gyromagnetic effect, a phenomenon discovered over a century ago. This effect, crucial for understanding the origins of magnetism, enables the coupling between various macroscopic rotational motions and electron spins. While higher rotational speeds intensify the effect, conventional mechanical rotations, typically, below 10,000 RPM, produce negligible results comparable to geomagnetic fluctuations, limiting applied research. Our studies demonstrate that spin current generation comparable to that of rare metals can be achieved through atomic rotations induced by GHzrange surface acoustic waves and the rotational motion of conduction electrons in metallic thin films with nanoscale gradient modulation of electrical conductivity. These effects, termed the acoustic gyromagnetic effect and the current-vorticity gyromagnetic effect, are significant in different contexts. The acoustic gyromagnetic effect is notable in high-conductivity materials like aluminum and copper, which are more abundant than conventional spintronics materials with strong spin-orbit interactions (SOIs). Conversely, the current-vorticity gyromagnetic effect requires a large conductivity gradient to produce current vorticity efficiently. This is achieved by using composition gradient structures from highly conductive metals to poorly conductive oxides or semiconductors. Consequently, unlike traditional strong-SOI materials, we can create highly efficient spin current generators with low energy dissipation due to reduced Joule loss.

Rights:

• Creative Commons BY-NC Attribution-NonCommercial 4.0 International
  

  © 2025 The Author(s). Published by National Institute for Materials Science in partnership with Taylor & Francis Group.
  This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. The terms on which this article has been published allow the posting of the Accepted Manuscript in a repository by the author(s) or with their consent.

Keyword: Spintronics, spin current

Date published: 2025-12-31

Publisher: Informa UK Limited

Journal:

• Science and Technology of Advanced Materials (ISSN: 14686996) vol. 26 issue. 1 2428153

Funding:

• Core Research for Evolutional Science and Technology JPMJCR19J4
• Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research / 23H01839
• Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research / 21H04565
• Ministry of Education, Culture, Sports, Science and Technology Quantum Leap Flagship Program / JPMXS0118067246
• Ministry of Education, Culture, Sports, Science and Technology Nanotechnology Platform Program / JPMXP09-F-21-AT-0085
• Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research / 24H00322
• Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research / 24H02233
• Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research / 23K26165
• Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research / 22K13997
• Japan Society for the Promotion of Science Grant-in-Aid for Research Activity Start-up / 22K20359

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1080/14686996.2024.2428153

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Updated at: 2025-04-03 08:30:07 +0900

Published on MDR: 2025-04-03 14:10:50 +0900