The purpose of this numerical study, performed within the micromagnetic framework and the dynamical matrix method, is to understand how the propagation of spin waves in a macrospin chain is affected by a configurational rearrangement of the magnetization, induced by a progressive variation of a magnetic field. Our macrospins are modelized through thin cylinders with elliptical cross sections that display a monodomain, bistable magnetization distribution; hence, the allowed magnetization configurations of the chain are either antiferromagnetic (AF) or ferromagnetic (FM). We illustrate the peculiar features of spin waves in the AF and FM configurations concerning the dispersion relations, phase amplitude variations and localization, and precession ellipticity, as a function of the applied field, particularly close to the critical field values at which the configurational rearrangements occur (AF-to-FM or vice versa). A remarkable effect that arises on the mode frequency and bandwidth across a configurational transition is the frequency invariance of specific Bloch waves, particularly attractive for processing the spin wave signals in low dissipation magnon-spintronic devices.

Spin wave propagation properties across configurational antiferro/ferro-magnetic transitions

Montoncello, F.
Co-primo
;
Giovannini, L.;
2018

Abstract

The purpose of this numerical study, performed within the micromagnetic framework and the dynamical matrix method, is to understand how the propagation of spin waves in a macrospin chain is affected by a configurational rearrangement of the magnetization, induced by a progressive variation of a magnetic field. Our macrospins are modelized through thin cylinders with elliptical cross sections that display a monodomain, bistable magnetization distribution; hence, the allowed magnetization configurations of the chain are either antiferromagnetic (AF) or ferromagnetic (FM). We illustrate the peculiar features of spin waves in the AF and FM configurations concerning the dispersion relations, phase amplitude variations and localization, and precession ellipticity, as a function of the applied field, particularly close to the critical field values at which the configurational rearrangements occur (AF-to-FM or vice versa). A remarkable effect that arises on the mode frequency and bandwidth across a configurational transition is the frequency invariance of specific Bloch waves, particularly attractive for processing the spin wave signals in low dissipation magnon-spintronic devices.
2018
Kuzma, D.; Montoncello, F.; Sobieszczyk, P.; Wal, A.; Giovannini, L.; Zieliński, P.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/2398289
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