Magnetic Coupling and Single-Ion Anisotropy in Surface-Supported Mn-Based Metal–Organic Networks

Abstract

The electronic and magnetic properties of Mn coordinated to\n1,2,4,5-tetracyanobenzene (TCNB) in the Mn-TCNB 2D metal-ligand networks have\nbeen investigated by combining scanning tunneling microscopy and X-ray magnetic\ncircular dichroism (XMCD) performed at low temperature (3 K). When formed on\nAu(111) and Ag(111) substrates the Mn-TCNB networks display similar geometric\nstructures. Magnetization curves reveal ferromagnetic (FM) coupling of the Mn\nsites with similar single-ion anisotropy energies, but different coupling\nconstants. Low-temperature XMCD spectra show that the local environment of the\nMn centers differs appreciably for the two substrates. Multiplet structure\ncalculations were used to derive the corresponding ligand field parameters\nconfirming an in-plane uniaxial anisotropy. The observed interatomic coupling\nis discussed in terms of superexchange as well as substrate-mediated magnetic\ninteractions.\n