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@PHDTHESIS{Costina:37416,
      author       = {Costina, Ioan},
      title        = {{T}he oxidation of the (100) surface of the intermetallic
                      alloys {N}i$_{3}${A}l and {C}o{A}l and the growth of {C}o on
                      the clean and oxidized {N}$_{3}${A}l(100) surface},
      volume       = {4033},
      issn         = {0944-2952},
      school       = {Univ. Düsseldorf},
      type         = {Dr. (Univ.)},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {PreJuSER-37416, Juel-4033},
      series       = {Berichte des Forschungszentrums Jülich},
      pages        = {VIII, 168 p.},
      year         = {2003},
      note         = {Record converted from VDB: 12.11.2012; Düsseldorf, Univ.,
                      Diss., 2003},
      abstract     = {The aim of this work was the preparation and
                      characterization of thin Al-oxide films an the (100) surface
                      of the intermetallic compounds Ni$_{3}$Al and COAT, as well
                      as the study of Co growth an the clean and oxidized
                      Ni$_{3}$Al(100) surface. The films were characterized by
                      Auger electron spectroscopy (AES), Low Energy Electron
                      Diffraction (LEED), Electron Energy Loss Spectroscopy (EELS)
                      and Scanning Tunneling Microscopy (STM). $\textbf{The clean
                      Ni$_{3}$Al(100) surface}$ The LEED pattern of clean
                      Ni$_{3}$Al(100) Shows a (1 x 1) structure. STM images of the
                      Ni$_{3}$Al(100) surface display flat and large terraces (500
                      - 1000 A) separated by steps with a step height of 3.5
                      $\mathring{A}$ which corresponds to the lattice constant of
                      Ni$_{3}$Al and represents a double atomic step. This
                      suggests that different terraces have always the Same
                      termination. $\textbf{Co/Ni$_{3}$Al(100)}$ At low coverage
                      (0 .1 ML) and 300 K, the cobalt deposited an the
                      Ni$_{3}$Al(100) surface shows a two-dimensional growth mode.
                      For deposition of 0.3 ML the nucleation takes also place in
                      the second layer. After deposition of 3.5 ML Co, the surface
                      consists of Co islands with a mean diameter of $\sim$
                      90$\mathring{A}$. Annealing at 700 K leads to the growth of
                      large terraces of fcc-Co which are arranged with the (100)
                      plane parallel to the (100) surface of the Substrate. Co is
                      stable an Ni$_{3}$Al(100) up to 750 K when it starts to
                      diffuse into the substrate. At 1100 K, Co is disappeared
                      completely from the surface via diffusion into the
                      Substrate. $\textbf{Al$_{2}$O$_{3}$/Ni$_{3}$Al(100)}$ At
                      room temperature oxygen adsorption an Ni$_{3}$Al(100) leads
                      to the formation of a thin amorphous Al-oxide
                      (a-Al$_{2}$O$_{3}$) layer ($\sim$ 5$\mathring{A}$).
                      Oxidation at 1100 K leads to formation of a well ordered
                      $\gamma'$-Al$_{2}$O$_{3}$ film with a thickness of $\sim$
                      10$\mathring{A}$. The STM images of the completely
                      oxide-covered surface exhibit hexagonal superstructures with
                      lattice constants of 18, 24 and 54 $\mathring{A}$. The band
                      gap of Al$_{2}$O$_{3}$ formed an Ni$_{3}$Al(100) amounts for
                      the amorphous film to $\sim$ 3.2 and to $\sim$ 4.3 eV for
                      the well ordered Al$_{2}$O$_{3}$ film, respectively and both
                      are strongly diminished with respect to the bulk values.
                      $\textbf{Co/Al$_{2}$O$_{3}$/Ni$_{3}$Al(100)}$ Co deposited
                      at room temperature an a Al$_{2}$O$_{3}$ film, which was
                      grown an Ni$_{3}$Al(100) at 1100 K, Shows a three
                      dimensional (Volmer-Weber) growth mode. After a nominal
                      deposition of 30 $\mathring{A}$ the 3D cobalt clusters have
                      a mean diameter of 70 $\mathring{A}$ and a roughness of
                      $\sim$ 10 $\mathring{A}$. Annealing at 700 and 900 K leads
                      to a coalescence of the Co clusters, and to a gradually
                      diffusion of Co through the oxide into the substrate. After
                      annealing at 1000 K the entire surface of alumina is Co
                      free. $\textbf{Al$_{2}$O$_{3}$/CoAl(100)}$ Oxygen adsorption
                      at 300 K leads to the formation of an amorphous
                      Al$_{2}$O$_{3}$ film an CoAl(100). Annealing at temperatures
                      between 800 - 1000 K induces a phase transformation from
                      a-Al$_{2}$O$_{3}$ into the $\theta$-Al$_{2}$O$_{3}$ phase,
                      which exhibits a (2x1) structure with respect to the
                      substrate. After annealing at temperatures > 1200 K a
                      transition to $\alpha$-Al$_{2}$O$_{3}$ occurs, while above
                      1300 K the decomposition and removal of the oxide film from
                      the surface is observed.},
      cin          = {ISG-3},
      cid          = {I:(DE-Juel1)VDB43},
      pnm          = {Kondensierte Materie},
      pid          = {G:(DE-Juel1)FUEK242},
      typ          = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
      url          = {https://juser.fz-juelich.de/record/37416},
}