Controlling Exchange Interaction and Magnetic Ordering in a van der Waals Ferromagnet

The magnetic exchange interaction is a key parameter that determines the magnetic ordering and magnetic anisotropy in strongly correlated materials and plays an important role in condensed matter physics and spintronics. Examples of magnetic exchange interaction modulation in low-dimensional magnetic materials have been demonstrated by strain engineering, element doping, and applying high pressure. However, the efficiencies of these modulation strategies for magnetic ordering controlling are still limited from the view of the atomic level. Here, the modulation of magnetic ordering in a van der Waals magnetic material (Fe_1-xCo_x)₃GaTe₂ by applying high pressure is demonstrated. The anti-ferromagnetic (AFM) ordering of (Fe_1-xCo_x)₃GaTe₂ can be tuned to ferromagnetic (FM) ordering by applying high pressure. Interestingly, the T_C value of pressurized (Fe_1-xCo_x)₃GaTe₂ (x = 0.24) first increases to ≈282 K and then decreases as the pressure increases, showing a dome shape in its phase diagram. Such observations indicate that the bonding length and bonding angle modulated by high pressure can efficiently influence the exchange interactions and corresponding magnetic states. Our observations provide a new material platform for understanding the magnetic exchange interactions in strongly correlated electronic systems.