Magnetic diffuse scattering in artificial kagome spin ice

TL;DR

This paper investigates magnetic correlations in a dynamic artificial kagome spin ice using soft x-ray scattering, revealing emergent phases, quasi-pinch-points, and similarities to bulk spin ice behavior, advancing nanomagnetic system analysis.

Contribution

It demonstrates the use of soft x-ray resonant magnetic scattering to study magnetic correlations in thermally active nanomagnet systems, showing kagome ice I phase features and quasi-pinch-points.

Findings

Kagome ice I phase correlations persist despite moment fluctuations.

Emergence of quasi-pinch-points in magnetic diffuse scattering.

Evolution of quasi-pinch-points into Coulomb phase pinch points at lower temperatures.

Abstract

The study of magnetic correlations in dipolar-coupled nanomagnet systems with synchrotron x-ray scattering provides a means to uncover emergent phenomena and exotic phases, in particular in systems with thermally active magnetic moments. From the diffuse signal of soft x-ray resonant magnetic scattering, we have measured magnetic correlations in a highly dynamic artificial kagome spin ice with sub-70-nm Permalloy nanomagnets. On comparing experimental scattering patterns with Monte Carlo simulations based on a needle-dipole model, we conclude that kagome ice I phase correlations exist in our experimental system even in the presence of moment fluctuations, which is analogous to bulk spin ice and spin liquid behavior. In addition, we describe the emergence of quasi-pinch-points in the magnetic diffuse scattering in the kagome ice I phase. These quasi-pinch-points bear similarities to the fully developed pinch points with singularities of a magnetic Coulomb phase, and continually evolve into the latter on lowering the temperature. The possibility to measure magnetic diffuse scattering with soft x rays opens the way to study magnetic correlations in a variety of nanomagnetic systems.