A prototype of the monoaxial chiral magnet ${\mathrm{CrNb}}_3{\mathrm{S}}_6$ exhibited two magnetostriction (MS) effects: (1) spontaneous MS due to the exchange interaction and spin-orbit coupling (SOC) at zero dc magnetic field ($H$) [Phys. Rev. B 102, 014446 (2020)] and (2) paramagnetic MS due to SOC and Zeeman energy at room temperature [Phys. Rev. B 105, 104412 (2022)]. ${\mathrm{CrNb}}_3{\mathrm{S}}_6$ has various magnetic structures, such as helimagnetic, first chiral soliton lattice (CSL-1), second CSL (CSL-2), CSL-2 with irreversibility, and forced ferromagnetic phases, resulting from the Dzyaloshinskii–Moriya interaction as a function of $H$ below the magnetic ordering temperature ($T_{\mathrm{c}}$). In this study, we conducted powder x-ray diffraction analyses to investigate the effects of $H$ and temperature ($T$) on the MS at the atomic level. The $T$ dependence of the lattice constants reveals that below $T_{\mathrm{c}}$, the MS depends on the magnetic structure. The MS below $T_{\mathrm{c}}$ is discussed in this study in terms of both the hybridization between the $z^2$ orbital of $\mathrm{Nb}\left(4f\right)$ and delocalized $a_1$ orbital of Cr and the structural symmetry of the ${\mathrm{CrS}}_6$ octahedron.

• Received 17 October 2022
• Revised 7 January 2023
• Accepted 2 February 2023

DOI:https://doi.org/10.1103/PhysRevB.107.054427