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@ARTICLE{Guo:44539,
      author       = {Guo, X. and Waser, R.},
      title        = {{E}lectrical properties of the grain boundaries of oxygen
                      ion conductors: acceptor-doped zirconia and ceria},
      journal      = {Progress in materials science},
      volume       = {51},
      issn         = {0079-6425},
      address      = {Amsterdam [u.a.]},
      publisher    = {Elsevier Science},
      reportid     = {PreJuSER-44539},
      pages        = {151},
      year         = {2006},
      note         = {Record converted from VDB: 12.11.2012},
      abstract     = {This article reviews the current understanding of the
                      electrical properties of the grain boundaries of
                      acceptor-doped zirconia and ceria, however, with an emphasis
                      on the grain-boundary defect structure. From an electrical
                      point of view, a grain boundary consists of a grain-boundary
                      core and two adjacent space-charge layers. The
                      grain-boundary cores of acceptor-doped zirconia. and ceria
                      are positively charged, probably owing to the oxygen vacancy
                      enrichment there. Oxygen vacancies are therefore depleted in
                      the space-charge layer. The grain-boundary conductivities of
                      acceptor-doped zirconia and ceria are at least two orders of
                      magnitude lower than the corresponding bulk values,
                      depending on temperature and dopant level. Such a phenomenon
                      is due to the facts: (1) that oxygen vacancies are severely
                      depleted in the space-charge layer, and (2) that the
                      grain-boundary impurity phase blocks the ionic transport
                      across the grain boundaries by decreasing the conduction
                      path width and constricting current lines. In materials of
                      high purity, the effect of the space-charge depletion layer
                      is dominant; however, in materials of normal purity, the
                      effect of the grain-boundary impurity phase is dominant. A
                      Schottky barrier model satisfactorily explains all the
                      phenomenological observations of the grain-boundary
                      electrical properties of materials of high purity, and
                      experimental evidence soundly supports the model. Various
                      factors (alumina addition and grain size) influencing the
                      grain-boundary electrical properties are discussed, and some
                      special aspects of nanocrystalline materials are highlighted
                      (c) 2005 Elsevier Ltd All rights reserved.},
      keywords     = {J (WoSType)},
      cin          = {IFF-IEM / JARA-FIT},
      ddc          = {530},
      cid          = {I:(DE-Juel1)VDB321 / $I:(DE-82)080009_20140620$},
      pnm          = {Kondensierte Materie},
      pid          = {G:(DE-Juel1)FUEK414},
      shelfmark    = {Materials Science, Multidisciplinary},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000233819400001},
      doi          = {10.1016/j.pmatsci.2005.07.001},
      url          = {https://juser.fz-juelich.de/record/44539},
}