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

TL;DR

This study reports the growth and detailed magnetic and electronic properties of bulk NaCrX2 (X=Te,Se,S) single crystals, revealing tunable magnetic anisotropy and conductivity, with potential applications in spintronics.

Contribution

It provides the first comprehensive experimental investigation of bulk NaCrX2 crystals, demonstrating tunable magnetic anisotropy and metal-insulator transitions, expanding understanding of 2D ferromagnetic semiconductors.

Findings

NaCrTe2 exhibits strong perpendicular magnetic anisotropy.

Se-doping tunes magnetic anisotropy to near isotropic.

NaCrSe2 shows ferromagnetic polarization under high magnetic field.

Abstract

Monolayer NaCrX2 (X=Te,Se,S) were theoretically proposed to be two-dimensional intrinsic ferromagnetic semiconductors while their 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 6 x 6 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. While for NaCrS2, robust antiferromagnetism is observed up to 70 kOe and two field-induced metamagnetic transitions are identified along H||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.