Organizing of magnetic skyrmions shows several forms similar to atomic arrays of solid states.Using Lorentz transmission electron microscopy, we report the first direct observation of a stable liquid-crystalline structure of skyrmions in chiral magnet Co 8.5 Zn 7.5 Mn 4 (110) thin film, caused by magnetic anisotropy and chiral surface twist. Elongated skyrmions are oriented and periodically arranged only in the <110> directions, whereas they exhibit short-range order along the <001> directions, indicating smectic skyrmion state. In addition, skyrmions possess anisotropic interaction with opposite sign depending on the crystal orientation, in contrast to existing isotropic interaction.

Topological defects embedded in or combined with domain walls have been proposed in various systems, some of which are referred to as domain wall skyrmions or domain wall bimerons. However, the experimental observation of such topological defects remains an ongoing challenge. Here, using Lorentz transmission electron microscopy, we report the experimental discovery of domain wall bimerons in chiral magnet Co-Zn-Mn(110) thin films. By applying a magnetic field, multidomain structures develop, and simultaneously, chained or isolated bimerons arise as the localized state between the domains with the opposite in-plane components of net magnetization. The multidomain formation is attributed to magnetic anisotropy and dipolar interaction, and domain wall bimerons are stabilized by the Dzyaloshinskii-Moriya interaction. In addition, micromagnetic simulations show that domain wall bimerons appear for a wide range of conditions in chiral magnets with cubic magnetic anisotropy. Our results promote further study in various fields of physics.

Theoretical studies have predicted that interactions between magnetic skyrmions and antiskyrmions give rise to various properties, such as unique arrangements, pair annihilation, topological transformation, and rectilinear and trochoidal motions that do not appear in only skyrmions or antiskyrmions. Recently, experimental studies have discovered that a Heusler material with the anisotropic Dzyaloshinskii–Moriya interaction shows a coexisting phase at 268 K and in-plane magnetic field-induced topological transformation of elliptical skyrmions and square-shaped antiskyrmions. Therefore, experimentally observing the coexisting phase and the topological transformation could be promising for developing skyrmion–antiskyrmion-based spintronics. However, such interactions and the detailed transformation mechanism remain unrevealed and unclear, respectively. Using Lorentz transmission electron microscopy experiments and micromagnetic simulations, we comprehensively study the properties in a coexisting phase of skyrmions and antiskyrmions in a Heusler material, Mn1.3Pt1.0Pd0.1Sn. Control of dipolar interaction (the sample thickness) allows us to realize a room-temperature coexisting phase. We find that the topological transformation occurs stochastically rather than deterministically, which can be explained by considering the magnetic point group and the direction of an in-plane magnetic field. We further observe isotropic long-range repulsive interaction between skyrmions and antiskyrmions in contrast to the conventional thought of the relative-position- and helicity-dependent short-range pairwise interactions, and deformation of skyrmions and antiskyrmions depending on the distance between them. Our simulations show that the deformation exerts significant influence on the magnetic energies and the energy landscape, contributing to the interaction. Our results provide insight into coexisting phases of skyrmions and antiskyrmions and a guide for developing skyrmion–antiskyrmion-based spintronics.