Ferromagnetic van der Waals (vdW) crystals are promising for future spintronics because they hold huge potential in terms of tunable chemical, mechanical, and physical properties. However, room-temperature vdW ferromagnets with high-quality perpendicular magnetic anisotropy (PMA) are still elusive, limiting their practical implementations for spintronic applications, such as nonvolatile memories. Here, we show that the magnetic properties of vdW ${\mathrm{Fe}}_3{\mathrm{Ge}\mathrm{Te}}_2$, including the Curie temperature and the PMA, can be tuned by interlayer exchange coupling (IEC). We demonstrate strong ferromagnetic and antiferromagnetic IECs between sputtered $\mathrm{Co}$ and vdW ${\mathrm{Fe}}_3{\mathrm{Ge}\mathrm{Te}}_2$ with $\mathrm{Pt}$ and $\mathrm{Ru}$ spacer layers, respectively. We find that ferromagnetic IEC enhances the Curie temperature of ${\mathrm{Fe}}_3{\mathrm{Ge}\mathrm{Te}}_2$ while maintaining PMA, which can exhibit 100% out-of-plane remanent magnetization above room temperature. On the other hand, antiferromagnetic coupling weakens the PMA, resulting in a multilevel magnetic hysteresis loop of ${\mathrm{Fe}}_3{\mathrm{Ge}\mathrm{Te}}_2$ even at temperatures as small as 10 K. These interlayered coupled 3D/2D heterostructures could emerge as prime candidates for practical vdW spintronic applications.

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• Exchange interaction
• Magnetic anisotropy
• Spin-orbit coupling
• Surface & interfacial phenomena
• Devices for digital logic, storage & processing
• Ferromagnets
• Magnetic multilayers
• van der Waals systems