3D tomographic imaging of skyrmionic cocoons using HERALDO

TL;DR

This paper demonstrates a novel 3D imaging technique using HERALDO to reconstruct the magnetization structure of skyrmionic cocoons in multilayer materials, revealing detailed internal features at nanoscale resolution.

Contribution

It introduces a vector tomographic reconstruction method with HERALDO for 3D magnetic textures, providing detailed insights into skyrmionic cocoons' structure and chirality.

Findings

Reconstructed 3D magnetization vectors with ~30 nm resolution.

Revealed vertical misalignment and chirality of skyrmionic cocoons.

Demonstrated HERALDO's effectiveness for nanoscale magnetic imaging.

Abstract

Uncovering the rich and intricate characteristics of three-dimensional (3D) magnetic textures is essential for functional materials such as magnetic multilayers, where the delicate balance of various magnetic interactions leads to complex 3D spin arrangements. Among these textures, skyrmionic cocoons-tubular 3D magnetic structures characterized by a closed magnetization surface wrapping around a core-have emerged as particularly intriguing. Stabilized by competing magnetic interactions, these textures reside within a fraction of the thickness of the magnetic material and exhibit a typical lateral size of approximately 100 nm. Here, we present a vector tomographic reconstruction of the 3D magnetization in aperiodic Pt/Co/Al chiral multilayers, where skyrmionic cocoons have been recently reported. Using soft X-ray Holography with Extended Reference by Autocorrelation Linear Differential Operator (HERALDO), we acquire tomographic projections of the magnetic configuration and reconstruct the full 3D magnetization vector field with a spatial resolution of approximately 30 nm, as determined by Fourier shell correlation (FSC). This resolution allows us to observe critical features of the cocoons, such as their vertical misalignment and their overall chirality. Our findings demonstrate that HERALDO-based vector tomography is a powerful approach for revealing the internal structure and vertical extent of these nanoscale magnetic textures, offering new experimental insights into their intrinsic behavior.