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@INPROCEEDINGS{Thoma:897114,
      author       = {Thoma, Henrik and Hutanu, Vladimir and Angst, Manuel and
                      Roth, Georg},
      title        = {{S}ingle and {D}ouble {P}olarized {N}eutron {D}iffraction
                      {O}ptions of {POLI} at {MLZ}},
      reportid     = {FZJ-2021-03612},
      year         = {2019},
      abstract     = {Polarized neutron diffraction (PND) is a powerful method to
                      investigate magnetic structures. It gives access to unique
                      information, which cannot be determined by non-polarized
                      neutron diffraction or with x-rays. Thus, it is a valuable
                      tool to untangle complex (e.g. chiral) magnetic structures.
                      Three different PND methods are implemented at the hot
                      neutron single crystal diffractometer POLI [1] at the Heinz
                      Maier-Leibnitz Zentrum (MLZ) in Garching, Germany. The first
                      technique, the so called flipping ratio (FR) method, uses a
                      single ³He spin filter cell (SFC) [2] to polarize the
                      incoming neutron beam. With a Mezei type double-coil spin
                      flipper between the polarizer and the high Tc
                      superconducting magnet at the sample position providing
                      fields up to 2.2 T, the ratio between the scattered
                      intensity with and without activated spin flipper is build.
                      All components of the setup were optimized for
                      short-wavelength neutrons and its performance successfully
                      tested [3]. Due to lifting counter mechanics, out of plane
                      Bragg reflections can be accessed and a large q-space
                      covered. Thus, this setup is well suited for the
                      high-quality determination of magnetic form factors, to
                      refine the local anisotropy in the magnetic susceptibility
                      tensor at the unit cell level and to reconstruct
                      magnetization density distribution maps.The second
                      technique, the so called uniaxial polarization analysis
                      (PA), is very similar to the FR method, expect the lifting
                      counter is replaced by the Decpol, containing a second ³He
                      SFC for polarization analysis after the scattering process.
                      Although the Bragg reflection access for this setup is
                      limited to the horizontal plane, valuable information about
                      the movement of magnetic domains or the magnetic moment
                      orientation can be collected.The third technique is the so
                      called spherical neutron polarimetry (SNP). Whereas the
                      sample was situated in a strong magnetic field for the
                      previous two PND options, the SNP method provides a zero
                      field at the sample position by using the Cryopad [4]. Thus,
                      the incoming polarization direction and the analysis axis
                      can be chosen arbitrary, giving precise access to
                      information about the phase difference between the nuclear
                      and magnetic structure and the magnetic moment values. This
                      is especially helpful for chiral and non-centrosymmetric
                      structures. Selected examples for each option are provided
                      and show the high performance of the PND setup of POLI.[1]
                      V. Hutanu, Heinz Maier-Leibnitz Zentrum, Journal of
                      large-scale research facilities, 1, A16 (2015)[2] V. Hutanu,
                      M. Meven, S. Masalovich et al., J. Phys.: Conf. Ser., 294,
                      012012 (2011)[3] H. Thoma, W. Luberstetter, J. Peters, and
                      V. Hutanu, J. Appl. Cryst. 51, 17-26 (2018)[4] V. Hutanu, W.
                      Luberstetter, E. Bourgeat-Lami, et al., Rev. Sci. Instrum.
                      87, 105108 (2016)},
      month         = {Mar},
      date          = {2019-03-11},
      organization  = {50th IFF Spring School "Scattering!
                       Soft, Functional and Quantum
                       Materials", Forschungszentrum Jülich
                       (Germany), 11 Mar 2019 - 22 Mar 2019},
      subtyp        = {After Call},
      cin          = {JCNS-FRM-II / JARA-FIT / JCNS-2 / JCNS-4 / MLZ},
      cid          = {I:(DE-Juel1)JCNS-FRM-II-20110218 /
                      $I:(DE-82)080009_20140620$ / I:(DE-Juel1)JCNS-2-20110106 /
                      I:(DE-Juel1)JCNS-4-20201012 / I:(DE-588b)4597118-3},
      pnm          = {6G4 - Jülich Centre for Neutron Research (JCNS) (FZJ)
                      (POF4-6G4) / 632 - Materials – Quantum, Complex and
                      Functional Materials (POF4-632)},
      pid          = {G:(DE-HGF)POF4-6G4 / G:(DE-HGF)POF4-632},
      experiment   = {EXP:(DE-MLZ)POLI-HEIDI-20140101},
      typ          = {PUB:(DE-HGF)24},
      url          = {https://juser.fz-juelich.de/record/897114},
}