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.