Long-Range Magnetic Order in Structurally Embedded Mesospin Metamaterials

TL;DR

This paper presents a scalable method to create structurally uniform magnetic metamaterials with intrinsic long-range antiferromagnetic order by embedding iron ions in a palladium matrix, avoiding lithographic disorder.

Contribution

The authors demonstrate a novel embedding technique that produces large-area, morphologically uniform magnetic metamaterials with spontaneous long-range magnetic order without annealing.

Findings

Achieved morphologically uniform arrays with embedded iron-ions.

Observed extended antiferromagnetic order in as-fabricated state.

Detected sharp magnetic Bragg peaks indicating long-range order.

Abstract

Engineered assemblies of interacting magnetic elements-magnetic metamaterials-provide a powerful route to tailor collective magnetic order and dynamics. By structuring matter at the mesoscale, they bridge atomic magnetism and macroscopic functionality, enabling emergent behaviour inaccessible in conventional materials. However, realizing large-area metamaterials that combine high morphological uniformity with intrinsic long-range order has remained challenging, largely due to the structural disorder inherent to lithographic fabrication. Here we demonstrate a scalable route to structurally and magnetically coherent metamaterials by embedding iron-ions to form mesospins within a non-magnetic thin film palladium host matrix. Using controlled implantation, we realize morphologically uniform arrays that spontaneously develop extended antiferromagnetic order in the as-fabricated state - without the need of external annealing or field cycling. Resonant X-ray scattering and microscopy reveal sharp magnetic Bragg peaks modulated by the mesospin form factor, evidencing long-range antiferromagnetic order coupled to structural coherence. This embedded architecture establishes a platform for exploring coherent spin-photon interactions and functional X-ray scattering in magnetic metamaterials free from lithographic topography and disorder.