Discovery of Intrinsic Ferromagnetism in Two-Dimensional van der Waals Crystals
(A) Emergence of ferromagnetism in a bilayer Cr2Ge2Te6, detected by Kerr effect; (B) Hysteresis loop of a six-layer Cr2Ge2Te6, and magnetic-field controlled transition temperature.
Discovered experimentally intrinsic ferromagnetism in a two-dimensional van der Waals crystals.
Significance and Impact
Opens a new materials platform for both fundamental science and spintronic applications.
- Long range magnetic order is strongly hampered by thermal fluctuations in 2D regime.
- The magnetocrystalline anisotropy stabilizes the ferromagnetic order at finite temperatures, leading to the observation of ferromagnetism in 2D Cr2Ge2Te6.
- Demonstrated unprecedented control of transition temperature of 2D Cr2Ge2Te6 by small magnetic fields which introduce effective anisotropy much greater than the intrinsic anisotropy.