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

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 T-C = 201 K and the modified Arrott plot, the precise critical exponents & beta; = 0.386(3) and & gamma; = 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 t(2g) electron of Cr atom. This work is an important asset for a series of CrxTey materials in future spintronic applications.

Automated summary

In this study, a large-area CrTe film deposited on an Al2O3 substrate was analyzed. The critical exponents β=0.386(3) and γ=1.391(2) were obtained through the analysis of critical isothermal magnetization and the modified Arrott plot. Furthermore, using the renormalization group theory, it was confirmed that CrTe exhibits a quasi-2D Heisenberg-like behavior with long-range interactions. Density functional theory calculations indicated that the CrTe band structure is mainly composed of Cr atom, and the total magnetic moments are determined by the polarized spin-up t(2g) electron of Cr atom.