Directional spin-wave coupling in an orthogonal magnetic waveguide system

Abstract

This work presents a comprehensive study of spin-wave coupling mechanisms in an orthogonal magnetic waveguide structure based on yttrium iron garnet (YIG) films. The investigated system comprises two lateral micro-waveguides connected via a central orthogonal waveguide, enabling a controlled interaction region for spin waves. Using micromagnetic simulations performed with MuMax3, the influence of the lateral channel gap (ranging from 40 to 200 µm) and the width of the central area on the collective dynamics of spin excitations was systematically analyzed. The results reveal that dipolar interactions between the waveguides induce mode splitting into symmetric and antisymmetric states, which leads to periodic energy transfer (beating) between the lateral channels. This phenomenon is governed by the difference in phase velocities of the coupled modes and can be precisely modulated by varying the geometric parameters of the structure. Frequency selectivity and spatial distribution of spin-wave power at the output ports are strongly dependent on the gap size, demonstrating efficient control of spin-wave routing. Furthermore, expanding the central region allows the observation of higher-order modes and the formation of caustic spin-wave patterns, attributed to interference effects in the intersection area. These findings underscore the critical role of dipolar coupling and structural geometry in controlling magnonic signal propagation and open avenues for the development of magnonic devices with low energy consumption, such as multiplexers and directional splitters. The demonstrated ability to manipulate spin-wave dynamics through structural engineering is promising for next-generation spintronic and magnonic applications.

Speaker

Andrey Grachev
Saratov State University
Russia

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