Magnetic properties of metal-organic coordination networks based on 3d transition metal atoms
| Autor: | Blanco-Rey, María, Sarasola, Ane, Nistor, Corneliu, Persichetti, Luca, Stamm, Christian, Piamonteze, Cinthia, Gambardella, Pietro, Stepanow, Sebastian, Otrokov, Mikhail M., Golovach, Vitaly N., Arnau, Andres |
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| Rok vydání: | 2018 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | The magnetic anisotropy and exchange coupling between spins localized at the positions of 3d transition metal atoms forming two-dimensional metal-organic coordination networks (MOCNs) grown on the Au(111) metal surface are studied. In particular, we consider MOCNs made of Ni or Mn metal centers linked by TCNQ (7,7,8,8-tetracyanoquinodimethane) organic ligands, which form rectangular networks with 1:1 stoichiometry. Based on the analysis of X-ray magnetic circular dichroism (XMCD) data taken at T= 2.5 K, we find that Ni atoms in the Ni-TCNQ MOCNs are coupled ferromagnetically and do not show any significant magnetic anisotropy, while Mn atoms in the Mn-TCNQ MOCNs are coupled antiferromagnetically and do show a weak magnetic anisotropy with in-planemagnetization. We explain these observations using both amodelHamiltonian based on mean-fieldWeiss theory and density functional theory calculations that include spin-orbit coupling. Our main conclusion is that the antiferromagnetic coupling between Mn spins and the in-plane magnetization of the Mn spins can be explained neglecting effects due to the presence of the Au(111) surface, while for Ni-TCNQ the metal surface plays a role in determining the absence of magnetic anisotropy in the system. Comment: 17 pages, 7 figures, submitted to Molecules (MDPI) on February 21st 2018, Supplementary Material in submit/2172866 |
| Databáze: | arXiv |
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