Three-dimensional spin-wave dynamics, localization and interference in a synthetic antiferromagnet

TL;DR

This study visualizes three-dimensional spin-wave dynamics in a synthetic antiferromagnet with nanoscale resolution, revealing depth-dependent profiles and interference patterns, thus advancing understanding of magnonic phenomena in nanostructures.

Contribution

It introduces a novel imaging technique for 3D spin-wave dynamics in synthetic antiferromagnets, enabling detailed analysis of complex interference patterns and their control.

Findings

Revealed depth-dependent spin-wave profiles due to interlayer dipolar interactions

Demonstrated complex 3D interference patterns in spin waves

Showed control of interference features by tuning magnetic system composition

Abstract

Spin waves are collective perturbations in the orientation of the magnetic moments in magnetically ordered materials. Their rich phenomenology is intrinsically three-dimensional; however, the three-dimensional imaging of spin waves has so far not been possible. Here, we image the three-dimensional dynamics of spin waves excited in a synthetic antiferromagnet, with nanoscale spatial resolution and sub-ns temporal resolution, using time-resolved magnetic laminography. In this way, we map the distribution of the spin-wave modes throughout the volume of the structure, revealing unexpected depth-dependent profiles originating from the interlayer dipolar interaction. We experimentally demonstrate the existence of complex three-dimensional interference patterns and analyze them via micromagnetic modelling. We find that these patterns are generated by the superposition of spin waves with non-uniform amplitude profiles, and that their features can be controlled by tuning the composition and structure of the magnetic system. Our results open unforeseen possibilities for the study and manipulation of complex spin-wave modes within nanostructures and magnonic devices.