Using Lorenz microscopy and small-angle electron diffraction, we directly present that the chiral magnetic soliton lattice (CSL) continuously evolves from a chiral helimagnetic structure in small magnetic fields in Cr(1/3)NbS2. An incommensurate CSL undergoes a phase transition to a commensurate ferromagnetic state at the critical field strength. The period of a CSL, which exerts an effective potential for itinerant spins, is tuned by simply changing the field strength. Chiral magnetic orders observed do not exhibit any structural dislocation, indicating their high stability and robustness in Cr(1/3)NbS2.

We investigate the interlayer magnetoresistance (MR) along the chiral crystallographic axis in the hexagonal chiral magnet CrNb 3 S 6 . In a region below the incommensurate-commensurate phase transition between the chiral soliton lattice and the forced ferromagnetic state, a negative MR is obtained in a wide range of temperature, while a small positive MR is found very close to the Curie temperature. Normalized data of the negative MR almost falls into a single curve and is well fitted by a theoretical equation of the soliton density, meaning that the origin of the MR is ascribed to the magnetic scattering of conduction electrons by a nonlinear, periodic, and countable array of magnetic soliton kinks. , belong to chiral space groups and are frequently referred to as chiral magnets. In chiral magnets, the combined effect of the symmetric Heisenberg exchange and the antisymmetric Dzyaloshinskii-Moriya (DM) interactions caused by the relativistic spin-orbit interaction [5,6] gives rise to a nontrivial spin texture and various interesting functions unique to chiral magnets. A coupling of conduction electrons with nontrivial spin textures has recently attracted great attention because of the ability to manipulate magnetotransport properties such as the topological Hall effect [7]. One promising candidate to realize this coupling is the chiral soliton lattice (CSL), which is formed in a chiral magnet under magnetic fields perpendicular to the chiral axis. The CSL is a nonlinear array of magnetic soliton kinks. It is naturally expected that each magnetic soliton kink works as a strong scattering potential for itinerant spins. Therefore, decreasing the number of magnetic soliton kinks may reduce the magnetoresistance (MR) and thus the CSL will present a nontrivial MR.In this Letter, we report the MR along the chiral axis in a hexagonal chiral magnetic crystal of CrNb 3 S 6 . We find that the normalized data of the negative MR almost falls into a single curve, and the revealed behavior indicates that the origin of the MR can be attributed to the magnetic scattering of conduction electrons by a nonlinear, periodic, and countable array of magnetic soliton kinks. Namely, we clarify the direct correlation between the experimentally measured MR and the analytically obtained soliton density as a function of the magnetic field.CrNb 3 S 6 is a typical monoaxial chiral magnet, which belongs to the space group of P6 3 22 [8]. It has a layered hexagonal structure of 2H-type NbS 2 intercalated by Cr atoms, so often expressed as Cr 1=3 NbS 2 . The size of the unit cell is 0.57 nm in the ab plane and 1.21 nm along the c axis [9,10]. Cr atoms are in the trivalent state and have localized electrons with spins of S ¼ 3=2, whereas conduction electrons are in an unfilled hybridized band of Nb and S. As a consequence of the chiral space group, the monoaxial DM interaction is allowed along the chiral c axis in CrNb 3 S 6 , which is given in the form of ÀD Á S 1 Â S 2 between localized neighboring spins S 1 and S 2 at Cr atoms. Here, D repres...

We present how macroscopically coherent ordering within a chiral state can be manifested in the physical properties within the context of an archetypical system-the chiral spin soliton lattice in a monoaxial chiral magnet CrNb 3 S 6. Using magnetotransport measurements and state-of-the-art Lorentz electron microscopy, we demonstrate spin soliton confinement in 1-μm-wide grains with different crystalline chirality and discretized magnetoresistance in 10-μm-wide crystals. Discretization effects are found to be prominent when the system size is reduced to the order of 10 μm along the chiral axis. A consequence that we identify is a robust coherence of the chiral soliton lattice against deformation. The spin configuration at the grain boundaries, which leads to soliton confinement, is experimentally clarified.

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