Twisting and tweezing the spin wave: on vortices, skyrmions, helical waves, and the magnonic spiral phase plate
| Autor: | Decheng Ma, Chenglong Jia, Alexander F. Schäffer, Jamal Berakdar |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Physics
Condensed Matter - Materials Science Angular momentum Condensed Matter - Mesoscale and Nanoscale Physics Spintronics Condensed matter physics business.industry Demagnetizing field Phase (waves) Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences Physics - Applied Physics Applied Physics (physics.app-ph) 02 engineering and technology Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials Magnetic field Magnetization 020210 optoelectronics & photonics Magnetic Phenomena Optics Spin wave Mesoscale and Nanoscale Physics (cond-mat.mes-hall) 0202 electrical engineering electronic engineering information engineering business |
| Zdroj: | Journal of Optics |
| Popis: | Spin waves are the low-energy excitations of magnetically ordered materials. They are key elements in the stability analysis of the ordered phase and have a wealth of technological applications. Recently, we showed that spin waves of a magnetic nanowire may carry a definite amount of orbital angular momentum components along the propagation direction. This helical, in addition to the chiral, character of the spin waves is related to the spatial modulations of the spin wave phase across the wire. It, however, remains a challenge to generate and control such modes with conventional magnetic fields. Here, we make the first proposal for a \textit{magnetic} spiral phase plate by appropriately synthesizing two magnetic materials that have different speeds of spin waves. It is demonstrated with full-numerical micromagnetic simulations that despite the complicated structure of demagnetization fields, a homogeneous spin wave passing through the spiral phase plate attains the required twist and propagates further with the desired orbital angular momentum. While excitations from the ordered phase may have a twist, the magnetization itself can be twisted due to internal fields and forms what is known as a magnetic vortex. We point out the differences between both types of magnetic phenomena and discuss their possible interaction. Comment: 6 pages, 5 figures |
| Databáze: | OpenAIRE |
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