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Controlling spin waves by inhomogeneous spin-transfer torques

Lorenzo Gnoatto1,*, Jean F. O. da Silva2, Artim L. Bassant3, Rai M. Menezes2,4, Rembert A. Duine1,3, Milorad V. Milošević2,†, and Reinoud Lavrijsen1

  • *Contact author: l.g.gnoatto@tue.nl
  • †Contact author: milorad.milosevic@uantwerpen.be
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Phys. Rev. B 113, 144416 – Published 10 April, 2026

DOI: https://doi.org/10.1103/lr39-lgtx

Abstract

We investigate the interplay between spin currents and spin waves in nanofabricated Permalloy waveguides with geometrical constrictions. Using propagating spin-wave spectroscopy, micromagnetic simulations, and analytical modeling, we provide experimental evidence that spin-wave phase can be modulated by inhomogeneous spin-transfer torques generated by current-density gradients shaped by the constriction geometry. Narrower constrictions enhance these gradients and modify the internal field for Damon–Eshbach spin waves, resulting in pronounced changes in spin-wave group velocity and phase. We show a quantitative experimental demonstration of deterministic spin-wave phase modulation enabled by geometry-engineered nonuniform spin-transfer torques. Beyond enabling a scalable route to magnonic interferometry—a building block for spin-wave-based computing—our findings establish a platform to control spin-wave dynamics in spatially varying current landscapes, relevant for analog-gravity experiments in condensed matter systems.

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Phys. Rev. B 113, 144416– Published 10 April, 2026
  • Received 1 October 2025
  • Accepted 5 March 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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