Scattering of exchange spin waves from a helimagnetic layer sandwiched between two semi-infinite ferromagnetic media
Poimanov, VD; Kuchko, AN; Kruglyak, VV
Date: 10 September 2020
Journal
Physical Review B
Publisher
American Physical Society
Publisher DOI
Abstract
We have calculated the scattering (reflection and transmission) coefficients of linear exchange spin waves
normally incident upon a helimagnetic layer sandwiched between two semi-infinite ferromagnetic media. Our
calculations show that, despite the helimagnetic order induced in the layer by the Dzyaloshinskii-Moriya
interaction ...
We have calculated the scattering (reflection and transmission) coefficients of linear exchange spin waves
normally incident upon a helimagnetic layer sandwiched between two semi-infinite ferromagnetic media. Our
calculations show that, despite the helimagnetic order induced in the layer by the Dzyaloshinskii-Moriya
interaction (DMI), the scattering is reciprocal and insensitive to the presence of the helimagnetic order in the
layer. This comes as a result of the disappearance of the DMI from the boundary conditions in the considered
geometry under the small-amplitude approximation and from the specific form of the nonreciprocity of the
spin-wave dispersion relation in the helimagnetic material. We show that the helimagnetic layer’s interfaces act
as a system of two semicrossed polarizers for the circularly polarized spin waves incident from the ferromagnetic
media. This results from the ellipticity of the magnetic precession induced by the easy-plane anisotropy in the
helimagnetic layer. Our calculations also reveal the importance of evanescent solutions to correctly describe
the spin-wave scattering in samples with elliptical precession. Our findings will aid development of magnonic
devices containing helimagnetic constituents.
Physics and Astronomy
Faculty of Environment, Science and Economy
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