Synthesis and anisotropic magnetic properties of LiCrTe single crystals with a triangular-lattice antiferromagnetic structure

We report on the synthesis of LiCrTe $_{\textrm{2}}$ single crystals and on their anisotropic magnetic properties. We have obtained these single crystals by employing a Te/Li-flux synthesis method. We find LiCrTe $_{\textrm{2}}$ to crystallize in a TlCdS $_{\textrm{2}}$ -type structure with cell parameters of a = 3.9512(5) Å and c = 6.6196(7) Å at T = 175 K. The content of lithium in these crystals was determined to be neary stoichiometric by means of neutron diffraction. We find a pronounced magnetic transition at $T^{\mathrm{{\,}ab}}_{\mathrm{N}}$ = 144 K and $T^{\mathrm{{\,}c}}_{\mathrm{N}}$ = 148 K, respectively. These transition temperatures are substantially higher than earlier reports on polycrystalline samples. We have performed neutron powder diffraction measurements that reveal that the long-range low-temperature magnetic structure of single crystalline LiCrTe $_{\textrm{2}}$ is an A-type antiferromagnetic structure. Our DFT calculations are in good agreement with these experimental observations. We find the system to be easy axis with moments oriented along the c -direction experimentally as well as in our calculations. Thereby, the magnetic Hamiltonian can be written as $H = H_{\mathrm{Heisenberg}} + \sum_i K_c (S_i^z)^2$ with $K_c = -0.34$ K (where $|S^z| = \frac{3}{2}$ ). We find LiCrTe $_{\textrm{2}}$ to be highly anisotropic, with a pronounced metamagnetic transition for $H \perp ab$ with a critical field of $\mu H_{MM}$ (5 K) ≈ 2.5 T. Using detailed orientation-dependent magnetization measurements, we have determined the magnetic phase diagram of this material. Our findings suggest that LiCrTe $_{\textrm{2}}$ is a promising material for exploring the interplay between crystal structure and magnetism, and could have potential applications in spin-based 2D devices.