title: Elucidating magnetic exchange and anisotropy in weakly coupled Mn(III) dimers.
abstract: High-frequency Electron Paramagnetic Resonance (HFEPR) measurements have been performed on both a single-crystal and powder samples of a weakly coupled antiferromagnetic dinuclear [Mn(III)](2) molecular magnet, [Mn(III)(2)L(2)(py)(4)], where L is the trianion of 3-(3-oxo-3-phenylpropionyl)-5-methylsalicylic acid, and py is pyridine. The experimental results were analyzed on the basis of a multispin Hamiltonian using both a perturbative approach and numerical simulations. It is found that the single-crystal HFEPR results provide a direct and simple means of determining both the axial anisotropy of the individual Mn(III) ions and the isotropic exchange coupling between them. Previously unpublished low-temperature magnetization data are then simulated using the same model Hamiltonian, yielding excellent agreement. This work highlights the limitations of widely used protocols for analyzing magnetic and powder EPR data obtained for multinuclear molecular magnets in which the exchange and single-ion anisotropies are comparable, thus emphasizing the value of single-crystal, multifrequency EPR measurements.
authors.affiliation: Department of Physics, University of Florida, Gainesville, Florida 32301, United States.
authors.forename: Junjie
authors.initials: J
authors.lastname: Liu
authors.forename: J
authors.initials: J
authors.lastname: Krzystek
authors.forename: Stephen
authors.initials: S
authors.lastname: Hill
authors.forename: Leoní
authors.initials: L
authors.lastname: Barrios
authors.forename: Guillem
authors.initials: G
authors.lastname: Aromí
mesh_terms: D016880:Anisotropy; D019281:Dimerization; D008280:Magnetics; D008345:Manganese / Q000737:chemistry*; D008958:Models, Molecular
chemical_list: D008345:Manganese