Enhanced Antiferromagnetic Phase in Metastable Self-Intercalated Cr_(1+x)Te₂ Compounds

Magnetic transition-metal dichalcogenides (TMDs) have been of particular interest due to their unique magnetic properties and two-dimensional (2D), layered structure that can be useful for engineering spintronics devices. Self-intercalation of transition metals inside the van der Waals (vdW) gaps of the TMDs can alter the structural and magnetic properties of the material and create new magnetic phases. Here we investigate two compounds with slight reductions in the Cr concentration of Cr₅Te₈, a ferromagnetic material previously reported to exhibit an antiferromagnetic (AFM) state with out-of-plane (OOP) Neel Vector at a temperature of 180 K. The two self-intercalated compounds, Cr_4.89Te₈ and Cr_4.81Te₈, form a metastable structure of Cr intercalants that can be manipulated by electron beam irradiation, as confirmed by X-ray diffraction (XRD) and transmission electron microscope (TEM) measurements. By altering the concentration of intercalated Cr atoms, magnetic measurements demonstrate a similar AFM phase found previously, but at a much higher Neel temperature (T_N) of approximately 241 K with an in-plane (IP) Neel Vector. In addition, an increased Curie temperature (T_c) with OOP easy-axis is confirmed by magnetoresistance (MR) measurements. This work provides a promising method of tuning magnetic and structural properties of the material by varying the concentration of intercalated atoms.