title: A four-coordinate cobalt(II) single-ion magnet with coercivity and a very high energy barrier.
abstract: Single-molecule magnets display magnetic bistability of molecular origin, which may one day be exploited in magnetic data storage devices. Recently it was realised that increasing the magnetic moment of polynuclear molecules does not automatically lead to a substantial increase in magnetic bistability. Attention has thus increasingly focussed on ions with large magnetic anisotropies, especially lanthanides. In spite of large effective energy barriers towards relaxation of the magnetic moment, this has so far not led to a big increase in magnetic bistability. Here we present a comprehensive study of a mononuclear, tetrahedrally coordinated cobalt(II) single-molecule magnet, which has a very high effective energy barrier and displays pronounced magnetic bistability. The combined experimental-theoretical approach enables an in-depth understanding of the origin of these favourable properties, which are shown to arise from a strong ligand field in combination with axial distortion. Our findings allow formulation of clear design principles for improved materials.
authors.affiliation: Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart D-70569, Germany.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Rechkemmer
authors.affiliation: Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart D-70569, Germany.
authors.forename: Frauke D
authors.initials: FD
authors.lastname: Breitgoff
authors.affiliation: Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstraße 34-36, Berlin D-14195, Germany.
authors.forename: Margarethe
authors.initials: M
authors.lastname: van der Meer
authors.affiliation: Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, Mülheim an der Ruhr D-45470, Germany.|Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria.
authors.forename: Mihail
authors.initials: M
authors.lastname: Atanasov
authors.affiliation: Laboratoire national des champs magnétiques intenses, CNRS-UJF-UPS-INS, Grenoble F-38042, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Hakl
authors.affiliation: Laboratoire national des champs magnétiques intenses, CNRS-UJF-UPS-INS, Grenoble F-38042, France.|Institute of Physics, Charles University in Prague, Prague CZ-12116, Czech Republic.
authors.forename: Milan
authors.initials: M
authors.lastname: Orlita
authors.affiliation: Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart D-70569, Germany.
authors.forename: Petr
authors.initials: P
authors.lastname: Neugebauer
authors.affiliation: Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, Mülheim an der Ruhr D-45470, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Neese
authors.affiliation: Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstraße 34-36, Berlin D-14195, Germany.
authors.forename: Biprajit
authors.initials: B
authors.lastname: Sarkar
authors.affiliation: Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart D-70569, Germany.
authors.forename: Joris
authors.initials: J
authors.lastname: van Slageren