Smectic Liquid-Crystalline Structure of Skyrmions in Chiral Magnet Co_(8.5)Zn_(7.5)Mn_4(110) Thin Film

摘要

The 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 liquidcrystalline structure of skyrmions in chiral magnet Co8.5Zn7.5Mn4(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 a smectic skyrmion state. In addition, skyrmions possess anisotropic interaction with an opposite sign depending on the crystal orientation, in contrast to existing isotropic interaction.