A biskyrmion consists of two bound, topologically stable skyrmion spin textures. These coffee-bean-shaped objects have been observed in real-space in thin plates using Lorentz transmission electron microscopy (LTEM). From LTEM imaging alone, it is not clear whether biskyrmions are surface-confined objects, or, analogously to skyrmions in non-centrosymmetric helimagnets, three-dimensional tube-like structures in bulk sample. Here, we investigate the biskyrmion form factor in single- and polycrystalline MnNiGa samples using small angle neutron scattering (SANS). We find that biskyrmions are not long-range ordered, not even in single-crystals. Surprisingly all of the disordered biskyrmions have their in-plane symmetry axis aligned along certain directions, governed by the magnetocrystalline anisotropy. This anisotropic nature of biskyrmions may be further exploited to encode information.
@article{arxiv.1902.09708,
title = {Oriented Three-Dimensional Magnetic Biskyrmion in MnNiGa Bulk Crystals},
author = {Xiyang Li and Shilei Zhang and Hang Li and Diego Alba Venero and Jonathan S White and Robert Cubitt and Qingzhen Huang and Jie Chen and Lunhua He and Gerrit van der Laan and Wenhong Wang and Thorsten Hesjedal and Fangwei Wang},
journal= {arXiv preprint arXiv:1902.09708},
year = {2019}
}