High wave vector non-reciprocal spin wave beams

TL;DR

This paper demonstrates unidirectional, high wave vector spin wave beams in thin YIG using nanowire arrays, revealing challenges in characterizing their propagation due to complex coupling effects.

Contribution

It introduces a downscaled chiral coupling technique for high wavevector exchange spin waves and analyzes their non-reciprocal transmission properties.

Findings

Unidirectional spin wave beams observed at wavevector lambda=80 nm.

Coupling efficiency shows non-monotonous field dependence.

Stray field inhomogeneity complicates propagation characterization.

Abstract

We report unidirectional transmission of micron-wide spin waves beams in a 55 nm thin YIG. We downscaled a chiral coupling technique implementing Ni80Fe20 nanowires arrays with different widths and lattice spacing to study the non-reciprocal transmission of exchange spin waves down to lambda = 80 nm. A full spin wave spectroscopy analysis of these high wavevector coupled-modes shows some difficulties to characterize their propagation properties, due to both the non-monotonous field dependence of the coupling efficiency, and also the inhomogeneous stray field from the nanowires.