Unidirectional spin wave propagation due to a saturation magnetization gradient

We demonstrate using micromagnetic simulations and a theoretical model that a gradient in the saturation magnetization (Ms) of a perpendicularly magnetized ferromagnetic film induces a nonreciprocal spin-wave propagation and, consequently, an asymmetric dispersion relation. The Ms gradient adds a li...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Physical review. B 2021-04, Vol.103 (14), Article 144411
Hauptverfasser: Borys, P., Kolokoltsev, O., Qureshi, N., Plumer, M. L., Monchesky, T. L.
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:We demonstrate using micromagnetic simulations and a theoretical model that a gradient in the saturation magnetization (Ms) of a perpendicularly magnetized ferromagnetic film induces a nonreciprocal spin-wave propagation and, consequently, an asymmetric dispersion relation. The Ms gradient adds a linear potential to the spin-wave equation of motion consistent with the presence of a force. We consider a transformation from an inertial reference frame in which the Ms is constant to an accelerated reference frame where the resulting inertial force corresponds to the force from the M s gradient. As in the Doppler effect, the frequency shift leads to an asymmetric dispersion relation. We show that under certain circumstances, unidirectional propagation of spin waves can be achieved, which is essential for the design of magnonic circuits. Our results become more relevant in light of recent experimental works in which a suitable thermal landscape is used to dynamically modulate the saturation magnetization.
ISSN:2469-9950
2469-9969
DOI:10.1103/PhysRevB.103.144411