@article{NeumannBuchsteinerMahleretal.2000,
  author    = {Neumann, Werner and Buchsteiner, Alexandra and Mahler, Willy and Geue, Thomas and Pietsch, Ullrich},
  title     = {Dielectric loss spectroscopy at fatty acid salt multilayers},
  year      = {2000},
  abstract  = {Dielectric loss spectroscopy (DLS) was performed at compact samples and lamellary organized Langmuir-Blodgett (LB) films from various fatty acid salts. Previous thermoanalytical measurements at compact samples revealed the appearance of two different phase transition temperatures; the lower one is related to the acid the second one to the acid salt molecules. In spite of ill defined electrical contacts with the film the characteristic DLS frequencies obtained from about 100nm thick multilayer films are similar to those recorded from bulk samples. No significant variations of frequencies were found changing the counter ions. Besides conductivity influence at low frequncies we found two relaxations related to the mobility of the dipolar carboxylat-metal group at about 100 and 10000Hz. One of these frequencies is related to the rotation around the chain axis. The strength of this relaxation increases significantly with increasing the sample temperature above 105°C. This temperature is connected with a structural phase transition observed by X-ray reflectometry. In case of Pb-stearate the results of the dielectric measurements help to interprete this structural change as a transition from an orthorhombic into a free-rotator phase. The uncorrelated rotation of molecules around their molecular axes initiates a much increased relaxation strength at the carboxylat-metal sites.},
  language  = {en}
}
@article{FruebingKremmerNeumannetal.2004,
  author    = {Fr{\"u}bing, Peter and Kremmer, Alexander and Neumann, Werner and Gerhard, Reimund and Guy, I. L.},
  title     = {Dielectric relaxation in piezo-, pyro- and ferroelectric polyamide 11},
  year      = {2004},
  abstract  = {Ferroelectric polyamide 11 films were prepared by melt-quenching, cold-drawing and electrical poling. Their ferroelectricity was studied by means of dielectric-hysteresis measurements. A remnant polarisation of up to 35 mC/m(2) and a coercive field of 75 MV/m were obtained. The piezoelectric d(33) coefficient and the pyroelectric coefficient of the films are reduced by annealing just below the melting region, but remain at about 3 pC/N and 8 muC/(m(2)K), respectively, during further heat treatment. Differential scanning calorimetry (DSC), dielectric relaxation spectroscopy (DRS) and thermally stimulated depolarisation (TSD) were applied for investigating the conformational changes induced by melt-quenching, cold-drawing and annealing. The results indicate that the cold-drawn film mainly consists of a rigid amorphous phase which exhibits considerably lower conductivity, no glass transition and consequently no dielectric a relaxation. Instead, an a, relaxation is found, which is related to chain motions in regions of the rigid amorphous phase where the amide-group dipoles are not perfectly ordered. Annealing removes imperfectly ordered structures, but does not affect the ferroelectric polarisation. Therefore, it may be concluded that essentially the a, relaxation causes the thermally non-stable part of the piezo- and pyroelectricity in polyamide 11},
  language  = {en}
}
@article{FruebingWegenerGerhardetal.1999,
  author    = {Fr{\"u}bing, Peter and Wegener, Michael and Gerhard, Reimund and Buchsteiner, Alexandra and Neumann, Werner and Brehmer, Ludwig},
  title     = {Different molecular mechanisms for the dielectric hysteresis and pyroelectricity in a poly(vinyl alcohol) with azobenzene-alkoxy side chains},
  issn      = {0277-786X},
  year      = {1999},
  abstract  = {By means of pyroelectrical measurements and dielectric spectroscopy as well as structural information from differential scanning calorimetry, it is shown that, in a poly(vinyl alcohol) with azobenzene-alkoxy side chains, pyroelctricity and dielectric hysteresis which are usually related to each other have different origins. The pyroelectric effect is explained with reversible dipole-density changes upon thermal expansion, whereas the dielectric hysteresis is proposed to result from a charge-carrier polarisation.},
  language  = {en}
}
@article{NeumannKasperKasper1991,
  author    = {Neumann, Werner and Kasper, Sabine and Kasper, Roberto},
  title     = {Discharge Currents in Polymer Solids between Blocking Contacts},
  isbn      = {0-7803-0113- 7},
  year      = {1991},
  language  = {en}
}
@article{BrumaMercerSchulzetal.1994,
  author    = {Bruma, Maria and Mercer, Frank W. and Schulz, Burkhard and Dietel, Reinhard and Neumann, Werner},
  title     = {Fluorinated poly(benzoxazole-imide)s},
  year      = {1994},
  language  = {en}
}
@book{HaenselNeumannWedell1993,
  author    = {H{\"a}nsel, Horst and Neumann, Werner and Wedell, Reiner},
  title     = {Physik : Bd. 1 Mechanik und W{\"a}rmelehre},
  volume    = {1},
  publisher = {Spektrum Akad. Verl.},
  address   = {Heidelberg},
  isbn      = {3-86025-046-9},
  pages     = {584 S.},
  year      = {1993},
  language  = {de}
}
@book{HaenselNeumannHudel1993,
  author    = {H{\"a}nsel, Horst and Neumann, Werner and Hudel, Erich},
  title     = {Physik : Bd. 2 Elektrizit{\"a}t, Optik, Raum und Zeit},
  volume    = {2},
  publisher = {Spektrum Akad. Verl.},
  address   = {Heidelberg},
  isbn      = {3-86025-304-2},
  pages     = {799 S.},
  year      = {1993},
  language  = {de}
}
@book{HaenselNeumannHudel1995,
  author    = {H{\"a}nsel, Horst and Neumann, Werner and Hudel, Erich},
  title     = {Physik : Bd. 3 Atome, Atomkerne, Elementarteilchen},
  volume    = {3},
  publisher = {Spektrum Akad. Verl.},
  address   = {Heidelberg},
  isbn      = {3-86025-313-1},
  pages     = {742 S.},
  year      = {1995},
  language  = {de}
}
@book{HaenselNeumannAlbrecht1996,
  author    = {H{\"a}nsel, Horst and Neumann, Werner and Albrecht, Fred},
  title     = {Physik : Bd. 4 Molek{\"u}le und Festk{\"o}rper},
  volume    = {4},
  publisher = {Spektrum Akad. Verl.},
  address   = {Heidelberg},
  isbn      = {3-86025-314-X},
  pages     = {758 S.},
  year      = {1996},
  language  = {de}
}
@article{HoepfnerFruebingNeumannetal.1996,
  author    = {H{\"o}pfner, Ulf and Fr{\"u}bing, Peter and Neumann, Werner and Kaminorz, Yvette and Brehmer, Ludwig},
  title     = {Polarization Processes of poly(DMDAAC) films studied by TSD current},
  year      = {1996},
  language  = {en}
}