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  • 1
    Electronic Resource
    Electronic Resource
    Spin density distribution of the conduction electrons in diperylene hexafluorophosphate analysed by high-resolution NMR (2000)
    Springer
    The European physical journal 15 (2000), S. 21-27 
    Details
    ISSN: 1434-6036
    Keywords: PACS. 76.60.Cq Chemical and Knight shifts - 71.20.-b Electron density of states and band structure of crystalline solids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: High-resolution 13C nuclear magnetic resonance with 1H cross polarization and 1H decoupling under magic angle spinning is measured for the quasi-one dimensional organic conductor diperylene hexafluorophosphate (including tetrahydrofurane solvent molecules) at temperatures between 160 K and 270 K. Ab initio molecular orbital calculations are used for chemical shift analysis and for assignment of Knight shifted lines and individual carbon positions. The coexistence of neutral perylene molecules and perylene radicals in the same radical cation salt is revealed. From Knight and chemical shifts we were able to distinguish two inequivalent perylene radicals within the conducting stack. The spin density distribution of the molecular electronic wave function is determined quantitatively for these radicals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100510051095
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  • 2
    Electronic Resource
    Electronic Resource
    The contribution of Gd and Mn neighbours to the Gd hyperfine field in GdMn6Ge6 (2000)
    Springer
    The European physical journal 18 (2000), S. 435-440 
    Details
    ISSN: 1434-6036
    Keywords: PACS. 76.60.Jx Effects of internal magnetic fields - 75.50.Gg Ferrimagnetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: With the help of 155,157Gd NMR in we derive the contribution of Gd and Mn neighbours to the hyperfine field at the rare earth site in the spiral spin phase of the intermetallic compound GdMn6Ge6. The substitution of Gd for Y atoms allows the determination of the separate contribution of remote Gd neighbours. The different temperature dependence of the hyperfine contributions of the Gd and Mn neighbours gives the possibility to estimate the transferred hyperfine field of Mn at the rare earth site both in magnitude and sign.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100510070030
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  • 3
    Electronic Resource
    Electronic Resource
    Magnetic susceptibility and electrical conductivity of Perylene radical cation salts (2000)
    Springer
    The European physical journal 16 (2000), S. 403-410 
    Details
    ISSN: 1434-6036
    Keywords: PACS. 71.30.+h Metal-insulator transitions and other electronic transitions - 72.80.Le Polymers; organic compound (including organic semiconductors)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Conduction electron properties of the quasi-one-dimensional conductors and (PE = perylene, THF = tetrahydrofurane) were investigated by measuring magnetic susceptibility and microwave conductivity in the temperature range from 10 K to 300 K. For quantitative analysis of the measurements a microscopic model was developed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100510070196
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  • 4
    Electronic Resource
    Electronic Resource
    Molecular reorientation in pyrene hexafluoroarsenate salts (2002)
    Springer
    The European physical journal 28 (2002), S. 289-297 
    Details
    ISSN: 1434-6036
    Keywords: PACS. 76.30.-v Electron paramagnetic resonance and relaxation – 61.66.Hq Organic compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: The quasi-one dimensional pyrene (PY) organic conductor (PY)7(PY)4(AsF6)4 . 4CH2Cl2shows parallel as well as 60° rotated PY radical cations in its stacks, but crystallizes in two different modifications I and II. One of the seven intra-stack pyrene molecules is susceptible to a reorientation by 60°, that is stable already at room temperature for modification II, but occurs at a hysteretic first order transition between 170 K and 240 K for modification I. Crystal structure, microwave conductivity and static magnetic susceptibility are typical for a quasi-one dimensional organic conductor with Peierls transition at TP = 73 K (mod. I) or TP = 105 K (mod. II). The pyrene radical packing is analysed by continuous wave and pulsed electron spin resonance measurements, using 9.45 GHz as well as 425 MHz as measuring frequency. Anisotropy of the conduction electron diffusion constant exceeds 1000 in the metallic phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e2002-00232-8
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  • 5
    Electronic Resource
    Electronic Resource
    Competing polarization mechanisms in the heavy-fermion paramagnet CeCu 6 (2002)
    Springer
    The European physical journal 26 (2002), S. 199-209 
    Details
    ISSN: 1434-6036
    Keywords: PACS. 76.60.-k Nuclear magnetic resonance and relaxation – 75.20.Hr Local moment in compounds and alloys; Kondo effect, valence fluctuations, heavy fermions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: Nuclear magnetic resonance (NMR) and relaxation of 63Cu and 65Cu in a powder sample of the heavy-fermion paramagnet CeCu6 is measured and analysed quantitatively. Five different Cu sites are accessible to a detailed analysis. We derive quadrupolar splitting frequencies, Ce to Cu transferred hyperfine field coupling constants, and transversal as well as longitudinal relaxation behaviour. Only small relaxation anomalies are observed at the orthorhombic to monoclinic structural phase transition of CeCu6. We point to the different importance of transferred hyperfine interaction and local conduction electron density for static or dynamic part, respectively, of Cu hyperfine interaction. The different sign of the transferred hyperfine interaction from Ce3+ to different Cu neighbours reveals the different competing interaction mechanisms, giving rise to the heavy-fermion paramagnetic behavior of CeCu6.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e20020081
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  • 6
    Electronic Resource
    Electronic Resource
    Overhauser shift of the electron spin-resonance line of Si:P at the metal-insulator transition: II. 29 Si contribution (2002)
    Springer
    The European physical journal 26 (2002), S. 455-465 
    Details
    ISSN: 1434-6036
    Keywords: PACS. 76.70.-r Magnetic double resonances and cross effects – 71.30.+h Metal-insulator transitions and other electronic transitions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: The electron-spin resonance (ESR) line of delocalised electrons shifts upon saturation due to the hyperfine interaction with the dynamically polarized nuclear spins. The 29 Si part of the Overhauser shift of the ESR line of phosphorus doped silicon (Si:P) is separated in the concentration range 2.7 ... 7.3×10 18 / cm 3 covering the metal-insulator transition. The Overhauser shift profiles, recorded versus 29 Si nuclear magnetic resonance (NMR) frequency, are asymmetric. Their dependence on temperature and ESR saturation compares reasonably with simulations. Time and NMR frequency dependence of the dynamic nuclear polarization is studied in detail. No pronounced variation of the 29 Si Overhauser shift profiles with P concentration is observed, but the maximum value of the shift profile decreases with increasing P concentration. In contrast to standard 29 Si NMR results, these measurements reveal the behaviour of the 29 Si nuclei close to the P doping sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e20020114
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  • 7
    Electronic Resource
    Electronic Resource
    Sample dependence of anisotropy and restriction of electron-spin diffusion in the quasi-one dimensional organic conductor (fluoranthene) $\mathsf{_2}$ PF $\mathsf{_6}$ (2003)
    Springer
    The European physical journal 35 (2003), S. 191-199 
    Details
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. As-grown and proton-irradiation damaged crystals of the quasi-one dimensional organic conductor (fluoranthene)2PF6 are studied by static magnetic field gradient spin echo electron spin resonance. The parallel-to-stack diffusion constant $D_{\parallel}$ varies sample dependent by a factor of 50, just like the ratio $D_{\parallel}/D_{\bot}$ . The restriction of free diffusive motion of the conduction electron spins of as-grown and microstructured crystals is analyzed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e2003-00268-2
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