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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.

Scientific Achievement
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.

Research Details

  • 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.

C. Gong, L. Li, Z. Li, H. Ji, A. Stern, Y. Xia, T. Cao, W. Bao, C. Wang, Y. Wang, Z.Q. Qiu, R.J. Cava, S.G. Louie, J. Xia, X. Zhang, Nature (2017) DOI: 10.1038/nature22060