Long‐Range Magnetic Exchange Coupling in Quasi‐2D CrTe Ferromagnetic Thin Films

Abstract

The 2D chromium telluride family (CrxTey) is an outstanding candidate for creating high‐density and dissipationless nanodevices because of its high Curie temperature, chiral spin patterns, and large saturation magnetic moment. However, the precise magnetic exchange mechanism and crucial phase transitional property of CrxTey must be fully analyzed. Herein, a large‐area CrTe (x:y = 1:1) single‐crystalline films deposited on an Al2O3 substrate. Based on the analysis of critical isothermal magnetization around the Curie temperature TC = 201 K and the modified Arrott plot, the precise critical exponents β = 0.386(3) and γ = 1.391(2) are obtained. Both their reliability and accuracy are also verified by Kouvel–Fisher theory, Widom scaling law, and scaling equation. Moreover, using the renormalization group theory, it is confirmed that CrTe belongs to a quasi‐2D Heisenberg‐like behavior with long‐range interactions. Finally, the density functional theory calculations indicate that, near the Fermi level, the CrTe band structure is mainly composed of Cr atom. The spin‐polarized density of states shows that the total magnetic moments are determined mainly by the polarized spin‐up t2g electron of Cr atom. This work is an important asset for a series of CrxTey materials in future spintronic applications.