Spin-Wave Channeling in Magnetization-Graded Nanostrips
Open Access
- 14 August 2022
- journal article
- research article
- Published by MDPI AG in Nanomaterials
- Vol. 12 (16), 2785
- https://doi.org/10.3390/nano12162785
Abstract
Magnetization-graded ferromagnetic nanostrips are proposed as potential prospects to channel spin waves. Here, a controlled reduction of the saturation magnetization enables the localization of the propagating magnetic excitations in the same way that light is controlled in an optical fiber with a varying refraction index. The theoretical approach is based on the dynamic matrix method, where the magnetic nanostrip is divided into small sub-strips. The dipolar and exchange interactions between sub-strips have been considered to reproduce the spin-wave dynamics of the magnonic fiber. The transition from one strip to an infinite thin film is presented for the Damon-Eshbach geometry, where the nature of the spin-wave modes is discussed. An in-depth analysis of the spin-wave transport as a function of the saturation magnetization profile is provided. It is predicted that it is feasible to induce a remarkable channeling of the spin waves along the zones with a reduced saturation magnetization, even when such a reduction is tiny. The results are compared with micromagnetic simulations, where a good agreement is observed between both methods. The findings have relevance for envisioned future spin-wave-based magnonic devices operating at the nanometer scale.Funding Information
- Agencia Nacional de Investigación y Desarrollo (Fondecyt 1210607, Fondecyt 11201249, Fondecyt 1201153)
- Basal Program for Centers of Excellence (AFB180001)
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