Disorder-resilient transition of Helical to Conical ground states in M${}_{1/3}$NbS${}_2$, M=Cr,Mn

Abstract

The discovery of chiral helical magnetism (CHM) in Cr${}_{1/3}$NbS${}_2$ and the stabilization of a chiral soliton lattice (CSL) has attracted considerable interest in view of their potential technological applications. However, there is an ongoing debate regarding whether the sister compound, Mn${}_{1/3}$NbS${}_2$, which shares the same crystal structure, exhibits similar nontrivial properties which rely on the stabilization of the lack of inversion symmetry at the magnetic ion. In this study, we conduct a comprehensive investigation of the magnetically ordered states of both compounds, using ${}^{53}$Cr, ${}^{55}$Mn and ${}^{93}$Nb nuclear magnetic resonance. Our results, supported by density functional calculations, detect in a high-quality single crystal of Cr${}_{1/3}$NbS${}_2$ all the signatures of the monoaxial CHM in a magnetic field, identifying it as a textbook NMR case. The detailed understanding of this prototypic behavior provides a reference for Mn${}_{1/3}$NbS${}_2$. Despite the much larger density of specific defects in this second single crystal, we confirm the presence of a CHM phase in the Mn compound, characterized by a very large critical field for the forced ferromagnetic phase ($\approx 5$ T for H$\parallel \hat{c}$).

10 pages, 7 figures, Supplemental MAterial