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@PHDTHESIS{Voigt:34787,
      author       = {Voigt, Jörg},
      title        = {{M}agnetische {S}trukturen in
                      $[{E}r\Tb]-{S}chichtsystemen:$ {E}influß der magnetischen
                      {N}achbarschaft und konkurrierender {A}nisotropien},
      volume       = {4087},
      issn         = {0944-2952},
      school       = {Techn. Hochsch. Aachen},
      type         = {Dr. (FH)},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {PreJuSER-34787, Juel-4087},
      series       = {Berichte des Forschungszentrums Jülich},
      pages        = {II, 144 p},
      year         = {2003},
      note         = {Record converted from VDB: 12.11.2012; Aachen, Techn.
                      Hochsch., Diss., 2003},
      abstract     = {The present work concerns the influence of the artificial
                      superstructure and competing anisotropies on the magnetic
                      structure in [Er$\vert$Tb] superlattices. Combining neutron
                      diffraction and resonance x-ray magnetic scattering (RXMS)
                      the long range magnetic ordering of localized 4f states can
                      be related to a coherent spin density wave in the conduction
                      bands of both Er and Tb. The direct observation of spin
                      density wave was made possible only by the improvements of
                      the RXMS technique, i.e., an excellent source at the
                      beamline 6id-b of the APS at the Argonne National Lab and a
                      very efficient polarization analysis to distinguish the
                      magnetic signal from the much stronger charge scattering. To
                      understand the magnetic behavior of a superlattice an
                      precise knowledge of the structural properties is needed.
                      Therefore the growth process for epitaxial multilayers was
                      optimized by in situ low energy electron diffraction and
                      Auger electron spectroscopy. Following recipes given in
                      literature for other rare earth systems, the growth
                      parameters have been adjusted for Er and Tb. In a
                      superlattice the quality of the interfaces is particularly
                      important. Their properties in complete multilayers have
                      been analysed ex situ by grazing incidence x-ray
                      diffraction. The interfaces extend over 3-4 atomic layers,
                      but the roughness is vertically correlated, as seen by the
                      diffuse scattering. Therefore a squared interface profile is
                      obtained locally even for small layer thicknesses. Wide
                      angle diffraction of neutrons and x-ray confirms the squared
                      structure of [Er$_{n_{Er}} \vert Tb_{n_{Tb}}$]
                      superlattices, the indices denoting the layer thickness in
                      atomic layers, with up to 150 repetitions of one bilayer
                      unit. Ferromagnetic order sets in at a temperature of 230 K,
                      if the Tb layer thickness is more then 20 atomic layers. The
                      ferromagnetic blocks are coupled, depending on temperature
                      and interlayer thickness. Bulk Tb undergoes a phase
                      transition to a helical magnetic structure at this
                      temperature. The suppression of the bulk helical structure
                      in Tb is due to epitaxial strains within the superlattice.
                      In contrast the [Er$_{20} \vert Tb_{5}$] sample forms a
                      modulated magnetic structure below 150 K. Additionally basal
                      plane ferromagnetic order appears below 40 K, with an
                      antiferromagnetic coupling of ordered layers. The RXMS
                      results confirm the existence of a common superlattice band
                      structure which is responsible for the magnetic proximity
                      effects. A common electronic band structure is found in an
                      Er$_{0,8}$Tb$_{0,2}$ film, too. The comparison with the
                      superlattice clarifies the difference between statistical
                      lattice site occupation and an artificial superstructure.
                      This opens the opportunity of tailored magnetic properties
                      by a man made structure.},
      cin          = {IFF-STM},
      cid          = {I:(DE-Juel1)VDB33},
      pnm          = {Kondensierte Materie},
      pid          = {G:(DE-Juel1)FUEK242},
      typ          = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
      url          = {https://juser.fz-juelich.de/record/34787},
}