Two-dimensional micrometer-sized CuFeSeS nanosheets: template-mediated chemical synthesis and magnetic regulation

The fundamental research and potential applications of magnetic two-dimensional (2D) ternary chalcogenides in spintronics have garnered considerable interest. Lessening the thickness of non-van der Waals (nvdWs) ternary chalcogenides to 2D structures can bring about novel physical phenomena and contribute to their potential applications in spintronics. In this paper, a template-mediated chemical synthesis was proposed to prepare nvdWs 2D micrometer-sized CuFeSeS composite nanosheets. Specifically, free-standing 2D nvdWs hexagonal CuFeSeS with a mean size of 2.6 μm was successfully achieved. The anisotropic growth of CuFeSeS was induced by the confinement effect of the template. Inspiringly, the 2D hexagonal CuFeSeS nanosheets with higher Fe content exhibit intrinsic ferromagnetic order, with a huge coercivity ( H C ) of 10.99 kOe at 5 K. The magnetism is regulated by varying the Fe content and reaction temperature. The valence changes of Fe, which form the ferromagnetic Fe 7 S 8 phase, play a crucial role in the magnetic transitions. This work enlightens the synthesis of 2D nvdWs ternary chalcogenides and promotes the potential applications of 2D hexagonal CuFeSeS nanosheets in spintronics. Graphical abstract