Curvature-induced spin-wave dynamics in Ni30Co70magnetic nanotubes: angular ferromagnetic resonance, multi-mode excitation, and magnonic control

Abhishek Kumar; Vishal Suri; Dhananjay Tiwari; Biswanath Chakraborty; Vivek K Malik; Debangsu Roy

doi:10.1088/1361-6528/ae71b5

Curvature-induced spin-wave dynamics in Ni₃₀Co₇₀magnetic nanotubes: angular ferromagnetic resonance, multi-mode excitation, and magnonic control

Nanotechnology. 2026 Jun 16;37(24). doi: 10.1088/1361-6528/ae71b5.

Authors

Abhishek Kumar¹, Vishal Suri², Dhananjay Tiwari³, Biswanath Chakraborty², Vivek K Malik⁴, Debangsu Roy¹

Affiliations

¹ Department of Physics, Indian Institute of Technology, Ropar, Rupnagar 140001, India.
² Indian Institute of Technology Jammu, Jammu, J&K 181221, India.
³ Photon Science Institute, The University of Manchester, M139PL Manchester, United Kingdom.
⁴ Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667, India.

PMID: 42171624
DOI: 10.1088/1361-6528/ae71b5

Abstract

Curvilinear magnetism offers a powerful route to engineer spin-wave phenomena beyond the limitations of planar architectures. In Curvilinear systems, geometry itself acts as an active control parameter. Magnetic nanotubes (MNTs) represent an archetypal three-dimensional (3D) platform. In MNTs, curvature induces emergent anisotropies, symmetry breaking, and nonreciprocal spin-wave transport without relying on interfacial Dzyaloshinskii-Moriya interactions. In this manuscript, we investigate spin-wave dynamics in thick-walled Ni₃₀Co₇₀MNTs using broadband, angular-dependent ferromagnetic resonance spectroscopy. We observe pronounced splitting and excitation of spin-wave modes that are absent in thin shells and planar films. The angular evolution of the spectra exhibits a maximum mode splitting nearφH=600. These modes arise from a competition between short-range exchange and curvature-enhanced dipolar interactions. Comparison of the measured resonance field separations with theoretical nanotube spin-wave spectra yields effective spin-wave wave-vectors (ksw) in the range of∼0.25-0.52 nm^-1. These values are in excellent agreement with existing theoretical predictions and BLS measurements on nanotubes. Our results provide ensemble-level experimental evidence of curvature-induced lifting of multi-mode excitation, and spectral asymmetry in MNTs. Furthermore, the present work advances both the fundamental understanding of spin-wave physics in 3D shells and the realization of reconfigurable, low-loss magnonic circuitry based on curvilinear nanomagnets.

Keywords: FMR; curvature-induced anisotropy; curvilinear magnetism; magnetic nanotubes; magnonics; mode hybridization; spin-wave dynamics.