Nonreciprocal magnon fluxonics upon ferromagnet/superconductor hybrids

TL;DR

This paper demonstrates nonreciprocal magnon scattering in ferromagnet/superconductor hybrids, showing tunable magnon bandgaps via low-dissipative currents and rectifying effects, enabling energy-efficient, fast-modulating magnonic devices.

Contribution

It introduces a method to control magnon bandgaps nonreciprocally using vortex lattice motion and current polarity, advancing hybrid magnonic device technology.

Findings

Magnon bandgap frequencies are tunable by low-dissipative currents.

Reversal of current polarity shifts magnon bandgaps.

Fast modulation of transmission characteristics on 10 ns timescale.

Abstract

Ferromagnet/superconductor heterostructures allow for the combination of unique physical phenomena offered by the both fields of magnetism and superconductivity. It was shown recently that spin waves can be efficiently scattered in such structures by a lattice of static or moving magnetic flux quanta (Abrikosov vortices), resulting in bandgaps in the spin-wave spectra. Here, we realize a nonreciprocal motion of a vortex lattice in nanoengineered symmetric and asymmetric pinning landscapes and investigate the non-reciprocal scattering of magnons on fluxons. We demonstrate that the magnon bandgap frequencies can be tuned by the application of a low-dissipative transport current and by its polarity reversal. Furthermore, we exploit the rectifying (vortex diode or ratchet) effect by the application of a 100 MHz-frequency ac current to deliberately realize bandgap up- or downshifts during one ac halfwave while keeping the bandgap frequency constant during the other ac halfwave. The investigated phenomena allow for the realization of energy-efficient hybrid magnonic devices, such as microwave filters with an ultra-high bandgap tunability of 10 GHz/mA and a fast modulation of the transmission characteristics on the 10 ns time scale.