Quantification of Magnetic Surface and Edge States in an FeGe Nanostripe by Off-Axis Electron Holography

Abstract

Whereas theoretical investigations have revealed the significant influence of magnetic surface and edge states on Skyrmonic spin texture in chiral magnets, experimental studies of such chiral states remain elusive. Here, we study chiral edge states in an FeGe nanostripe experimentally using off-axis electron holography. Our results reveal the magnetic-field-driven formation of chiral edge states and their penetration lengths at 95 and 240 K. We determine values of saturation magnetization M S by analyzing the projected in-plane magnetization distributions of helices and Skyrmions. Values of M S inferred for Skyrmions are lower by a few percent than those for helices. We attribute this difference to the presence of chiral surface states, which are predicted theoretically in a three-dimensional Skyrmion model. Our experiments provide direct quantitative measurements of magnetic chiral boundary states and highlight the applicability of state-ofthe-art electron holography for the study of complex spin textures in nanostructures.

Evolution and competition between chiral spin textures in nanostripes with D 2d symmetry

“…Furthermore, it is worth mentioning that, although the formation of the antiskyrmions is strongly affected by the confinement, the antiskyrmions always form in the middle of the nanostripe, unlike edge-mediated skyrmions presented in the B20 material FeGe (30,33). We repeated these experiments for a wider nanostripe with a width of 490 nm (see Fig.…”

“…This time, the helix Q-vectors are rotated by φ compared to the helices in the nanostripe discussed above. This can be contrasted with B20 materials, where the confined geometry of a nanostripe induces a strong anisotropy to the helix orientation so that they always form perpendicular or parallel to the edge, as discussed in (30,33). Although the two types of helices are not aligned parallel or perpendicular to the nanostripe direction in the D 2d system for the nanostripe shown in Figs.…”

Next-Generation Information Technology Systems for Fast Detectors in Electron Microscopy

“…Detector data with a high information content can be analyzed by using forward models in a feedback loop that compare acquired data from multiple detectors with simulations based on models of the specimen. This approach is already used with very good results to reconstruct the magnetization states of samples (Caron, 2018) (Song, et al, 2018). The implementation of such an analysis would require a hybrid system that combines fast iterative optimization of a model with the handling of a massive data set.…”

Robust Antiskyrmion Phase in Bulk Tetragonal Mn–Pt(Pd)–Sn Heusler System Probed by Magnetic Entropy Change and AC‐Susceptibility Measurements

“…With regard to the experimental observation of skyrmions, evidence for the existence of skyrmion lattices can be established through real space identification using Lorentz transmission microscopy, and electron holography, and reciprocal space detection through small angle neutron scattering . Nevertheless, these sophisticated techniques require special sample preparation methods and are inaccessible to many laboratories.…”