Increased Curie temperature and enhanced perpendicular magneto anisotropy of Cr₂Ge₂Te₆/NiO heterostructure

Van der Waals (vdW) materials with ferromagnetic properties down to few layers such as CrI₃ and Cr₂Ge₂Te₆ have recently attracted a lot of attention due to their potential in spintronic applications. However, the Curie temperature (T_C) of these vdW has remained relatively low. Here, we report increased T_C and enhanced perpendicular magnetic anisotropy in Cr₂Ge₂Te₆ (CGT) flakes interfaced with antiferromagnetic insulator NiO for a wide range of CGT thicknesses (5-200 nm).
Measurements of the same flake by polar magneto optic Kerr effect (MOKE) microscopy before and after coating NiO reveal a hysteresis loop with a square shape and larger coercive field for the CGT/NiO heterostructure. Furthermore, the maximum T_C observed for CGT/NiO reached ~120K, almost double the T_C of CGT alone (~60K). These observations suggest that interfacing van der Waals ferromagnets with other materials could provide a venue to engineer their magnetic properties. [1]

[1] H. Idzuchi, A. E. Llacsahuanga Allcca, X. C. Pan, K. Tanigaki and Y. P. Chen (2019), Increased Curie temperature and enhanced perpendicular magneto anisotropy of Cr₂Ge₂Te₆/NiO heterostructure. Manuscript submitted for publication.