Chiral helimagnetism and stability of magnetic textures in MnNb$_3$S$_6$

Abstract: We analyze the nature of the modulated magnetic states in a micromagnetic model for the monoaxial chiral magnet MnNb$_3$S$_6$ for which the Dzyaloshinskii-Moriya interaction and the dipolar interaction compete evenly. We show that the interplay between these interactions lead to a complex phase diagram including ferromagnetic states, fan-like states, in-plane stripes patterns and chiral soliton lattices. In particular, stripe patterns and chiral soliton lattices comprise non-trivial topological states with fixed chirality. The obtained phase diagram exhibits strong dependency on the thickness and on the strength of the Dzyaloshinskii-Moriya interaction. Our results can help to understand the magnetic properties of systems such as MnNb$_3$S$_6$.