Intrinsic 2D XY ferromagnetism in a van der Waals monolayer
Bedoya Pinto, A., Ji, J.R., Pandeya, A.K., Gargiani, P., Valvidares, M., Sessi, P., Taylor, J.M., Radu, F., Chang, K., Parkin, S.S.P.
Abstract
The recent discovery of magnetism in two dimensional 2D materials has inspired efforts to understand its nature. Whereas the magnetism of monolayers of chromium iodide CrI3 can be understood in terms of out of plane magnetic anisotropy, the related material chromium chloride CrCl3 has spins that lie in the plane. Bedoya Pinto et al. used molecular beam epitaxy to grow monolayers of CrCl3 on graphene and studied its magnetic properties. Using x ray magnetic circular dichroism measurements, the authors found that monolayer CrCl3 is a ferromagnet, unlike bulk CrCl3, which is antiferromagnetic. The scaling of the signal in the critical region indicated that the material belongs to the 2D XY universality class, distinct from Ising magnetism, which some other 2D magnets exhibit