Coexistence of structural and magnetic phases in the van der Waals ferromagnet CrI3

Amidst the members of the family of layered materials, chromium triiodide was the first one to demonstrate the persistence of a ferromagnetic hysteresis down to the monolayer as well as a layer-dependent transition from a ferromagnetic to an antiferromagnetic state¹. Following this discovery, a plethora of studies appeared providing evidence that the origin of this thickness-dependent magnetism is a change in the crystalline stacking order, thus revealing a strong coupling between magnetism and crystal structure^2,3,4. However, to date, bulk CrI3 keeps hosting deep conundrums such as the existence of a peak at 50 K in the in-plane magnetization curve, and controversies, such as having a range of temperatures for the crystalline phase transition^4,5. Combining muon spin rotation, magnetization and low temperature X-ray diffraction measurements we reveal the temperature evolution of three different magnetic states together with different crystalline phases beyond the monoclinic/rhombohedral dichotomy, showcasing a far more intricate scenario than the one already known.

References

[1] B. Huang et al., Nature, 546, 2017.

[2] X. Guo et al., ACS Nano, 15, 6, 2021.

[3] Z. Sun et al., Nature, 572, 2019.   

[4] M. A. McGuire et al., Chem. Mat., 27, 2015.

[5] Z. Wang et al., Nat. Comm., 9, 2018.