Anisotropic magnetic properties and tunable conductivity in two-dimensional layered NaCrX2 (X=Te,Se,S) single crystals

Monolayer NaCrX2 (X=Te,Se,S) was theoretically proposed to be a two-dimensional intrinsic ferromagnetic semiconductor, although its physical properties have not been thoroughly investigated in bulk single crystals. We report the single-crystal growth, structural, magnetic, and electronic transport properties of NaCr(Te1-xSex)(2) (0 <= x <= 1) and NaCrS2. For NaCr(Te1-xSex)(2), the strong perpendicular magnetic anisotropy of NaCrTe2 can be gradually tuned to be a nearly isotropic one by Se doping. Meanwhile, a systematic change in the conductivity with increasing x is observed, displaying a doping-induced metal-insulator-like transition. Under magnetic field larger than 30 kOe, both NaCrTe2 and NaCrSe2 can be polarized to a ferromagnetic state. However, for NaCrS2, robust antiferromagnetism is observed up to 70 kOe, and two field-induced metamagnetic transitions are identified along H parallel to ab. These intriguing properties together with the potential to be exfoliated down to few-layer thickness make NaCrX2 (X=Te,Se,S) promising for exploring spintronic applications.