Ferrimagnetic state of the metal-organic framework CrCl2(pyz)2

Van der Waals layered ferromagnetic compounds with high two-dimensional electronic conductivity holds strong potential for quantum computing, future unconventional superconductors, catalysts, batteries, and fuel cells.We suggest a minimal theoretical model to understand the magnetic properties of the metal-organic framework CrCl2(pyz)2 (pyz=pyrazine).Using a Hubbard model we show that the groundstate is dominated by a specific configuration of delocalized electrons on the pyz sites with a ferrimagnetic coupling to the localized spins on the Cr sites.This model suggests a magnetic moment of 2B which is remarkably close to the experimental value of 1.8B [K. S. Pedersen et al., Nat.Chem. 10, 1056-1061(2018)].From Weiss mean-field theory we predict a weak ferromagnetic Cr-Cr coupling of 0.9 meV.This is consolidated by second order perturbation theory of the RKKY interaction yielding a Cr-Cr coupling of 5 meV.Understanding the interactions in these types of compounds can facilitate designs of metal-organic compounds with tailored magnetic properties.