Magnon-Fluxon interaction in a ferromagnet/superconductor heterostructure

O. V. Dobrovolskiy; R. Sachser; T. Brächer; T. Fischer; V. V. Kruglyak; R. V. Vovk; V. A. Shklovskij; M. Huth; B. Hillebrands; A. V. Chumak

doi:10.1038/s41567-019-0428-5

arXiv · 1901.06156

Magnon-Fluxon interaction in a ferromagnet/superconductor heterostructure

O. V. Dobrovolskiy·R. Sachser·T. Brächer·T. Fischer·V. V. Kruglyak·R. V. Vovk·V. A. Shklovskij·M. Huth·B. Hillebrands·A. V. Chumak

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Abstract

Ferromagnetism and superconductivity are most fundamental phenomena in condensed matter physics. Entailing opposite spin orders, they share an important conceptual similarity: Disturbances in magnetic ordering in magnetic materials can propagate in the form of spin waves (magnons) while magnetic fields penetrate superconductors as a lattice of magnetic flux quanta (fluxons). Despite a rich choice of wave and quantum phenomena predicted, magnon-fluxon coupling has not been observed experimentally so far. Here, we clearly evidence the interaction of spin waves with a flux lattice in ferromagnet/superconductor Py/Nb bilayers. We demonstrate that, in this system, the magnon frequency spectrum exhibits a Bloch-like band structure which can be tuned by the biasing magnetic field. Furthermore, we observe Doppler shifts in the frequency spectra of spin waves scattered on a flux lattice moving under the action of a transport current in the superconductor.

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O. V. Dobrovolskiy, R. Sachser, T. Brächer, T. Fischer, V. V. Kruglyak, R. V. Vovk, V. A. Shklovskij, M. Huth, B. Hillebrands, A. V. Chumak. 2019-01-18. Magnon-Fluxon interaction in a ferromagnet/superconductor heterostructure. https://doi.org/10.1038/s41567-019-0428-5

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