Dynamic Fingerprint of Controlled Structural Disorder in Artificial Spin Lattices

TL;DR

This study introduces a tunable artificial spin lattice platform to systematically explore how controlled structural disorder influences collective spin-wave dynamics, revealing a quantitative link between static disorder and dynamic spectral complexity.

Contribution

It provides the first experimental demonstration of a direct correlation between controlled structural disorder and dynamic spectral complexity in artificial spin systems.

Findings

Spectral modes evolve from discrete to dense with increasing disorder

A quantitative correlation between static disorder and spectral complexity is established

Disordered states exhibit richer microstate diversity than driven states

Abstract

Investigating the emergence of complexity in disordered interacting systems, central to fields like spin glass physics, remains challenging due to difficulties in systematic experimental tuning. We introduce a tunable artificial spin lattice platform to directly probe the connection between controlled structural disorder and collective spin-wave dynamics. By precisely varying positional and rotational randomness in Ni81Fe19 nanobar arrays from periodic to random, we map the evolution from discrete spectral modes to a complex, dense manifold. Crucially, we establish a quantitative correlation between information-theoretic measures of static disorder and the dynamic spectral complexity derived from the GHz spin-wave response. This correlation provides a dynamic fingerprint of an increasingly complex energy landscape resulting from tuned disorder. Furthermore, thermal probe via thermal Brillouin light scattering reveal significantly richer microstates diversity in disordered states than driven probe using broadband ferromagnetic resonance. Our work presents a unique experimental testbed for studying how the ingredients of glassy physics manifest in high-frequency dynamics, offering quantitative insights into the onset of complexity in interacting nanomagnet systems.