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Abstract Antiferromagnetic spintronics is an emerging area of quantum technologies that leverage the coupling between spin and orbital degrees of freedom in exotic materials. Spin-orbit interactions allow spin or angular momentum to be injected via electrical stimuli to manipulate the spin texture of a material, enabling the storage of information and energy. In general, the physical process is intrinsically local: spin is carried by an electrical current, imparted into the magnetic system, and the spin texture will then rotate in the region of current flow. In this study, we show that spin information can be transported and stored “non-locally" in the material Fe x NbS2. We propose that collective modes can manipulate the spin texture away from the flowing current, an effect amplified by strong magnetoelastic coupling of the ordered state. This suggests a novel way to store and transport spin information in strongly spin-orbit coupled magnetic systems.

Layered transition-metal dichalcogenides (TMDCs) host a plethora of interesting physical phenomena ranging from charge order to superconductivity. By introducing magnetic ions into 2H-TA_{2} (T=Nb, Ta; A=S, Se), the material forms a family of magnetic intercalated TMDCs M_{x}TA_{2} (M=3d transition metal). Recently, Fe_{1/3+δ}NbS_{2} has been found to possess intriguing resistance switching and magnetic memory effects coupled to the Néel temperature of T_{N}∼45 K [Maniv et al., Nat. Phys. 17, 525 (2021)NPAHAX1745-247310.1038/s41567-020-01123-w; Sci. Adv. 7, eabd8452 (2021)SACDAF2375-254810.1126/sciadv.abd8452]. We present comprehensive single crystal neutron diffraction measurements on underintercalated (δ∼-0.01), stoichiometric, and overintercalated (δ∼0.01) samples. Magnetic defects are usually considered to suppress magnetic correlations and, concomitantly, transition temperatures. Instead, we observe highly tunable magnetic long-ranged states as the Fe concentration is varied from underintercalated to overintercalated, that is, from Fe vacancies to Fe interstitials. The under- and overintercalated samples reveal distinct antiferromagnetic stripe and zigzag orders, associated with wave vectors k_{1}=(0.5,0,0) and k_{2}=(0.25,0.5,0), respectively. The stoichiometric sample shows two successive magnetic phase transitions for these two wave vectors with an unusual rise-and-fall feature in the intensities connected to k_{1}. We ascribe this sensitive tunability to the competing next-nearest neighbor exchange interactions and the oscillatory nature of the Ruderman-Kittel-Kasuya-Yosida mechanism. We discuss experimental observations that relate to the observed intriguing switching resistance behaviors. Our discovery of a magnetic defect tuning of the magnetic structure in bulk crystals Fe_{1/3+δ}NbS_{2} provides a possible new avenue to implement controllable antiferromagnetic spintronic devices.

We perform high-field magnetization measurements on the triangular lattice antiferromagnet Fe_{1/3}NbS_{2}. We observe a plateau in the magnetization centered at approximately half the saturation magnetization over a wide range of temperature and magnetic field. From density functional theory calculations, we determine a likely set of magnetic exchange constants. Incorporating these constants into a minimal Hamiltonian model of our material, we find that the plateau and the Z_{3} symmetry-breaking ground state both arise from the competition of interplane and intraplane exchange interactions. These findings are pertinent to the magnetoelectric properties of Fe_{1/3}NbS_{2}, which allow electrical switching of antiferromagnetic textures at relatively low current densities.