Tunable magnonic crystal in a hybrid superconductor--ferrimagnet nanostructure

TL;DR

This paper introduces a novel tunable magnonic crystal created by a periodic superconducting strip pattern, allowing control of spin-wave spectra through external magnetic fields and structural modifications.

Contribution

It presents a new approach to tunable magnonic systems using superconductor-induced inhomogeneous fields, verified by semi-analytical and numerical methods.

Findings

Spin-wave spectrum can be tuned by the superconductor's stray field.

Modifying superconducting strip width affects internal magnetic fields.

The approach enables unprecedented control in magnonic structures.

Abstract

One of the most intriguing properties of magnonic systems is their reconfigurability, where an external magnetic field alters the static magnetic configuration to influence magnetization dynamics. In this paper, we present an alternative approach to tunable magnonic systems. We studied theoretically and numerically a magnonic crystal induced within a uniform magnetic layer by a periodic magnetic field pattern created by the sequence of superconducting strips. We showed that the spin-wave spectrum can be tuned by the inhomogeneous stray field of the superconductor in response to a small uniform external magnetic field. Additionally, we demonstrated that modifying the width of superconducting strips and separation between them leads to the changes in the internal field which are unprecedented in conventional magnonic structures. The paper presents the results of semi-analytical calculations for realistic structures, which are verified by finite-element method computations.