title: Theoretical insights into the magnetostructural correlations in Mn3-based single-molecule magnets.
abstract: Density functional theory (DFT) and the valence bond configuration interaction (VBCI) model have been applied to the oximato-based Mn(III)(3)O single-molecule magnets (SMMs), allowing one to correlate the Mn(III)-Mn(III) exchange coupling energy (J) with the bridging geometry in terms of two structural angles: the Mn-O-N-Mn torsion angle (γ) and the Mn(3) out-of-plane shift of O (angle δθ). Using DFT, a two-dimensional (γ, δθ) energy surface of J is derived and shown to yield essentially good agreement with the reported J values deduced from magnetic susceptibility data on trigonal oximato-bridged Mn(3) SMMs. VBCI is used to understand and analyze the DFT results. It is shown that the exchange coupling in these systems is governed by a spin-polarization mechanism inducing a pronounced and dominating ferromagnetic exchange via the oximato bridge as opposed to kinetic exchange, which favors a weaker and antiferromagnetic exchange via the bridging oxide. In the light of these results, a discussion of the exchange coupling in the Mn(6) family of the SMM with a record demagnetization barrier is given.
authors.affiliation: Paul Scherrer Institute and ETH Zürich, CH-5232 Villigen PSI, Switzerland. mihail.atanasov@aci.uni-heidelberg.de
authors.forename: M
authors.initials: M
authors.lastname: Atanasov
authors.forename: B
authors.initials: B
authors.lastname: Delley
authors.forename: F
authors.initials: F
authors.lastname: Neese
authors.forename: P L
authors.initials: PL
authors.lastname: Tregenna-Piggott
authors.forename: M
authors.initials: M
authors.lastname: Sigrist