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Author: Büchner, Bernd × Author: Popov, Alexey A. × End date: 2019 × Start date: 2014 ×

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Now showing 1 - 3 of 3
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    High Blocking Temperature of Magnetization and Giant Coercivity in the Azafullerene Tb 2 @C 79 N with a Single-Electron Terbium–Terbium Bond
    (Weinheim : Wiley-VCH, 2019) Velkos, Georgios; Krylov, Denis S.; Kirkpatrick, Kyle; Spree, Lukas; Dubrovin, Vasilii; Büchner, Bernd; Avdoshenko, Stanislav M.; Bezmelnitsyn, Valeriy; Davis, Sean; Faust, Paul; Duchamp, James; Dorn, Harry C.; Popov, Alexey A.
    The azafullerene Tb 2 @C 79 N is found to be a single-molecule magnet with a high 100-s blocking temperature of magnetization of 24 K and large coercivity. Tb magnetic moments with an easy-axis single-ion magnetic anisotropy are strongly coupled by the unpaired spin of the single-electron Tb−Tb bond. Relaxation of magnetization in Tb 2 @C 79 N below 15 K proceeds via quantum tunneling of magnetization with the characteristic time τ QTM =16 462±1230 s. At higher temperature, relaxation follows the Orbach mechanism with a barrier of 757±4 K, corresponding to the excited states, in which one of the Tb spins is flipped. © 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.
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    Methane as a selectivity booster in the arc-discharge synthesis of endohedral fullerenes: Selective synthesis of the single-molecule magnet Dy2TiC@C80and Its Congener Dy2TiC2@C80
    (Hoboken, NJ : Wiley, 2015) Junghans, Katrin; Schlesier, Christin; Kostanyan, Aram; Samoylova, Nataliya A.; Deng, Qingming; Rosenkranz, Marco; Schiemenz, Sandra; Westerström, Rasmus; Greber, Thomas; Büchner, Bernd; Greber, Thomas; Popov, Alexey A.
    The use of methane as a reactive gas dramatically increases the selectivity of the arc‐discharge synthesis of M‐Ti‐carbide clusterfullerenes (M=Y, Nd, Gd, Dy, Er, Lu). Optimization of the process parameters allows the synthesis of Dy2TiC@C80‐I and its facile isolation in a single chromatographic step. A new type of cluster with an endohedral acetylide unit, M2TiC2@C80, is discovered along with the second isomer of M2TiC@C80. Dy2TiC@C80‐(I,II) and Dy2TiC2@C80‐I are shown to be single‐molecule magnets (SMM), but the presence of the second carbon atom in the cluster Dy2TiC2@C80 leads to substantially poorer SMM properties.
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    Endohedral metal-nitride cluster ordering in metallofullerene-NiII(OEP) complexes and crystals : A theoretical study
    (Cambridge : RSC Publ., 2019) Dubrovin, Vasilii; Gan, Li-Hua; Büchner, Bernd; Popov, Alexey A.; Avdoshenko, Stanislav M.
    The ordering of endohedral clusterfullerenes Sc3N@C80 and YSc2N@C80 co-crystallized with Ni(OEP) and isolated complexes with Ni(OEP) have been investigated theoretically. Having used multiple orientations of M3N clusters inside the cages with Fibonacci sampling, we describe the effect of intermolecular interactions on the orientation of the endohedral cluster. © the Owner Societies.