Nehrkorn, J., Höck, M., Brüger, M., Mutka, H., Schnack, J., Waldmann, O.
The tetrameric Ni(II) spin cluster Ni4Mo12 has been studied by INS. The data were analyzed extensively in terms of a very general spin Hamiltonian, which includes antiferromagnetic Heisenberg...
Quantum Phase Interference and Neel-Vector Tunneling in Antiferromagnetic Molecular Wheels (2009)
Waldmann, O., Stamatatos, T. C., Christou, G., Güdel, H. U., Sheikin, I., Mutka, H.
The antiferromagnetic molecular wheel Fe18 of eighteen exchange-coupled Fe(III) ions has been studied by measurements of the magnetic torque, the magnetization, and the inelastic neutron scattering...
Datta, S., Waldmann, O., Kent, A. D., Milway, V. A., Thompson, L. K., Hill, S.
High-frequency electron paramagnetic resonance (EPR) studies of the antiferromagnetic Mn-$[3\times 3]$ molecular grid clearly reveal a breaking of the $\Delta S = 0$ selection rule, providing direct...
Schnelzer, L., Waldmann, O., Horvatić, M., Ochsenbein, S. T., Krämer, S., Berthier, C., ...
The 1H-NMR spectrum and nuclear relaxation rate 1/T_1 in the antiferromagnetic wheel CsFe8 were measured to characterize the previously observed magnetic field-induced low-temperature phase around...
Standing Spin Waves in an Antiferromagnetic Molecular Cr6 Horseshoe (2007)
Ochsenbein, S. T., Waldmann, O., Sieber, A., Carver, G., Bircher, R., Güdel, H. U., ...
The antiferromagnetic molecular finite chain Cr6 was studied by inelastic neutron scattering. The observed magnetic excitations at 2.6 and 4.3 meV correspond, due to the open boundaries of a finite...
Quantum spin clusters with dominant antiferromagnetic Heisenberg exchange interactions typically exhibit a sequence of field-induced level crossings in the ground state as function of magnetic field....
Waldmann, O., Bircher, R., Carver, G., Sieber, A., Güdel, H. U., Mutka, H.
The Q dependence of the inelastic neutron scattering (INS) intensity of transitions within the ground-state spin multiplet of single-molecule magnets (SMMs) is considered. For these transitions, the...
Standing spin waves in an antiferromagnetic molecular Cr6 horseshoe (2007)
Ochsenbein, ST, Waldmann, O, Sieber, A, Carver, G, Bircher, R, Gudel, HU, ...
Koizumi, S, Nihei, M, Shiga, T, Nakano, M., Nojiri, H, Bircher, R, ...
E-band excitations in the magnetic Keplerate molecule Fe30 (2006)
The low-temperature excitations in the magnetic Keplerate molecule Fe30 as calculated by linear spin-wave theory (SWT), modified linear SWT, and spin-level mean-field theory (SLMFT) are compared to...
Quantum dynamics of the Neel vector in the antiferromagnetic molecular wheel CsFe8 (2006)
Waldmann, O., Dobe, C., Güdel, H. U., Mutka, H.
The inelastic neutron scattering (INS) spectrum is studied for the antiferromagnetic molecular wheel CsFe8, in the temperature range 2 - 60 K, and for transfer energies up 3.6 meV. A qualitative...
An iron(III) phosphonate cluster containing a nonanuclear ring (2006)
Yao, H. C., Wang, J. J., Ma, Y. S., Waldmann, O., Du, W. X., Song, Y., ...
This communication reports the first example of cyclic ferric clusters with an odd number of iron atoms capped by phosphonate ligands, namely, [Fe9(m-OH)7(m-O)2(O3PC6H9)8-(py)12]. The magnetic...
Waldmann, O., Güdel, H. U., Kelly, T. L., Thompson, L. K.
The magnetic susceptibility, and low-temperature magnetization curve, of the [3 x 3] grid [Mn(III)4Mn(II)5(2poap-2H)6](ClO4)10.10H2O is analyzed within a spin Hamiltonian approach. The Hilbert space...
Supramolecular Co(II)-[2 x 2] grids: Metamagnetic behavior in a single molecule (2006)
Waldmann, O., Ruben, M., Ziener, U., Müller, P., Lehn, J. M.
The magnetic anisotropy of the supramolecular [2 x 2] grid [Co(II)4L4]8+, with a bis(bipyridyl)-pyrimidine based ligand L, was investigated by single-crystal magnetization measurements at low...
Sieber, A., Foguet-Albiol, D., Waldmann, O., Ochsenbein, S. T., Carver, G., Mutka, H., ...
The low-lying magnetic excitations in the dimer of single-molecule magnets (Mn4)2 are studied by inelastic neutron scattering as a function of hydrostatic pressure. The anisotropy parameters D and...
A family of ferro- and antiferromagnetically coupled decametallic chromium(III) wheels (2006)
Low, DM, Rajamaran, G, Helliwell, M, Timco, G, Van Slageren, J, Sessoli, R, ...
The synthesis and crystal structures of a family of decametallic CrIII molecular wheels are reported, namely [Cr10(OR)20(O2CR)10] [R=Me, R=Me (1), Et (2); R=Et, R=Me (3), Et (4); R=CMe3,...
Field-induced magnetoelastic instabilities in antiferromagnetic molecular wheels (2006)
Waldmann, O., Dobe, C., Ochsenbein, S. T., Güdel, H. U., Sheikin, I.
The magnetic torque of the antiferromagnetic molecular wheel CsFe8 was studied down to 50 mK and up to 28 T. Below about 0.5 K phase transitions were observed at the field-induced level crossings...
Supramolecular Co(II)-[2 x 2] grids: Metamagnetic behavior in a single molecule. (2006)
Waldmann, O., Ruben, M., Ziener, U., Müller, P., Lehn, J.M.
Inorganic Chemistry, 45(2006) S.6535-40
Waldmann, O., Carver, G., Dobe, C., Biner, D., Sieber, A., Güdel, H. U., ...
Time-resolved inelastic neutron scattering measurements on an array of single-crystals of the single-molecule magnet Mn12ac are presented. The data facilitate a spectroscopic investigation of the...
Field-induced magnetoelastic instabilities in antiferromagnetic molecular wheels (2005)
Waldmann, O., Dobe, C., Ochsenbein, S. T., Güdel, H. U., Sheikin, I.
The magnetic torque of the antiferromagnetic molecular wheel CsFe8 was studied down to 50 mK and in fields up to 28 T. Below ca. 0.5 K phase transitions were observed at the field-induced...
Many molecular magnetic clusters, such as single-molecule magnets, are characterized by spin ground states with defined total spin S exhibiting zero-field-splittings. In this work, the spectroscopic...
Quantum tunneling of the Neel vector in antiferromagnetic [3 x 3] grid molecules (2005)
Based on numerical calculations it is shown that the antiferromagnetic grid molecule Mn-[3 x 3] is a very promising candidate to experimentally detect the phenomenon of quantum tunneling of the Neel...
Supramolecular chemistry has allowed the production, by self-assembly, of inorganic complexes with a [N x N] square matrix-like configuration of N^2 metal centers. Interest in these systems is driven...
Mesoscopic quantum coherence in antiferromagnetic molecular clusters (2004)
Waldmann, O., Dobe, C., Mutka, H., Furrer, A., Güdel, H. U.
From inelastic neutron scattering experiments, we demonstrate quantum tunneling of the Neel vector in the antiferromagnetic molecular ferric wheel CsFe8. Analysis of the linewidth of the tunneling...
Quantum-magneto oscillations in a supramolecular Mn(II)-[3 x 3] grid (2004)
Waldmann, O., Carretta, S., Santini, P., Koch, R., Jansen, A. G. M., Amoretti, G., ...
The magnetic grid molecule Mn(II)-[3 x 3] has been studied by high-field torque magnetometry at 3He temperatures. At fields above 5 T, the torque vs. field curves exhibit an unprecedented oscillatory...
Inelastic neutron scattering study of the molecular grid nanomagnet Mn-[3x3] (2004)
Guidi, T, Carretta, S, Santini, P, Liviotti, E, Magnani, N, Mondelli, C, ...
Quantum magneto-oscillations in a supramolecular Mn(II)-[3x3] grid (2004)
Waldmann, O., Carretta, S., Santini, P., Koch, R., Jansen, A. G. M., Amoretti, G., ...
The magnetic grid molecule Mn(II)-[3x3] has been studied by high-field torque magnetometry at He-3 temperatures. At fields above 5 T, the torque versus field curves exhibit an unprecedented...
Elementary excitations in the cyclic molecular nanomagnet Cr8 (2003)
Waldmann, O., Guidi, T., Carretta, S., Mondelli, C., Dearden, A. L.
Combining recent and new inelastic neutron scattering data for the molecular cyclic cluster Cr8 produces a deep understanding of the low lying excitations in bipartite antiferromagnetic Heisenberg...
For powder samples of polynuclear metal complexes the dependence of the inelastic neutron scattering intensity on the momentum transfer Q is known to be described by a combination of so called...
Ferromagnetic coupling and magnetic anisotropy in molecular Ni(II) squares (2003)
Koch, R., Waldmann, O., Mueller, P., Reimann, U., Saalfrank, R. W.
We investigated the magnetic properties of two isostructural Ni(II) metal complexes [Ni4Lb8] and [Ni4Lc8]. In each molecule the four Ni(II) centers form almost perfect regular squares. Magnetic...
Waldmann, O., Koch, R., Schromm, S., Müller, P., Bernt, I., Saalfrank, R. W.
At low temperatures, the magnetization of the molecular ferric wheel NaFe$_6$ exhibits a step at a critical field $B_c$ due to a field-induced level-crossing. By means of high-field torque...
Intrinsic Tunneling in Cuprates and Manganites (2001)
Heim, S., Nachtrab, T., Moessle, M., Kleiner, R., Koch, R., Rother, S., ...
The most anisotropic high temperature superconductors like Bi2Sr2CaCu2O8, as well as the recently discovered layered manganite La1.4Sr1.6Mn2O7 are layered metallic systems where the interlayer...
Studies of hydrocarbon formation and redeposition in ITER-relevant divertor chamber conditions
Fussmann, Gerd, Baudach, M., Bohmeyer, W., Koch, B., Krenz, G., Markin, A., ...