Controlled Synthesis of 2D Ferromagnetic/Antiferromagnetic Cr₇Te₈/MnTe Vertical Heterostructures for High-Tunable Coercivity

Two-dimensional ferromagnetic/antiferromagnetic (2D-FM/AFM) heterostructures are of great significance to realize the application of spintronic devices such as miniaturization, low power consumption, and high-density information storage. However, traditional mechanical stacking can easily damage the crystal quality or cause chemical contamination residues for 2D materials, which can result in weak interface coupling and difficulty in device regulation. Chemical vapor deposition (CVD) is an effective way to achieve a high-quality heterostructure interface. Herein, high-quality interface 2D-FM/AFM Cr₇Te₈/MnTe vertical heterostructures were successfully synthesized via a one-pot CVD method. Moreover, the atomic-scale structural scanning transmission electron microscope (STEM) characterization shows that the interface of the vertical heterostructure is clear and flat without an excess interface layer. Compared to the parent Cr₇Te₈, the coercivity (H_C) of the high-quality interface Cr₇Te₈/MnTe heterostructure is significantly reduced as the thickness of MnTe increases, with a maximum decrease of 74.5% when the thickness of the MnTe nanosheet is around 30 nm. Additionally, the H_C of the Cr₇Te₈/MnTe heterostructure can also be regulated by applying a gate voltage, and the H_C increases or decreases with increasing positive or negative gate voltages. Thus, the effective regulation of H_C is essential to improving the performance of advanced spintronic devices (e.g., MRAM and magnetic sensors). Our work will provide ideas for spin controlling and device application of 2D-FM/AFM heterostructures.