  A special cross-tie (SCT) domain wall was discovered in the helimagnet MnCoSi
alloy via the magnetic vector field tomography in Lorentz transmission electron
microscopy (LTEM). Different to the traditional cross-tie (TCT) domain wall
where the convergent/divergent magnetic moment configuration line up one by
one, the relative large Bloch type sub-walls emerge in this brand-new SCT
domain wall and two mutually perpendicular rotation axes coexist in this
special feature. The straight magnetic stripes accompanied with the unraveled
domain walls hint the complex mechanism to form this SCT structure.
Interestingly, different orientation of this domain wall in LTEM can easily
exhibit various magnetic features, including meron/antimeron chains or bimeron
strings.
