On the Ferrimagnetic State of CrCl$_2$(pyz)$_2$

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Main Authors: Guttesen, Freja Schou, Hedegård, Per
Format: Preprint
Published: 2024
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author Guttesen, Freja Schou
Hedegård, Per
author_facet Guttesen, Freja Schou
Hedegård, Per
contents 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 CrCl$_2$(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 $2μ_B$ which is remarkably close to the experimental value of $1.8 μ_B$ [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 $\approx 0.9$ meV. This is consolidated by second order perturbation theory of the RKKY interaction yielding a Cr-Cr coupling of $\approx 5$ meV. Understanding the interactions in these types of compounds can facilitate designs of metal-organic compounds with tailored magnetic properties.
format Preprint
id arxiv_https___arxiv_org_abs_2411_09662
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the Ferrimagnetic State of CrCl$_2$(pyz)$_2$
Guttesen, Freja Schou
Hedegård, Per
Strongly Correlated Electrons
Materials Science
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 CrCl$_2$(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 $2μ_B$ which is remarkably close to the experimental value of $1.8 μ_B$ [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 $\approx 0.9$ meV. This is consolidated by second order perturbation theory of the RKKY interaction yielding a Cr-Cr coupling of $\approx 5$ meV. Understanding the interactions in these types of compounds can facilitate designs of metal-organic compounds with tailored magnetic properties.
title On the Ferrimagnetic State of CrCl$_2$(pyz)$_2$
topic Strongly Correlated Electrons
Materials Science
url https://arxiv.org/abs/2411.09662