MLZ is a cooperation between:

Technische Universität München> Technische Universität MünchenHelmholtz-Zentrum Geesthacht> Helmholtz-Zentrum GeesthachtForschungszentrum Jülich> Forschungszentrum Jülich
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MLZ (eng)

Lichtenbergstr.1
85748 Garching

HEiDi

Single crystal diffractometer on hot source

HEiDi HEiDi

The single crystal diffractometer HEiDi is designed for detailed studies on structural and magnetic properties of single crystals using unpolarised neutrons and Bragg’s Law:

2 dhkl  sin (Θ) = λ

Because of the large variety of short wavelengths and resolutions, HEiDi is suitable for studies on a lot of crystalline compounds – many of them of potential interest for energy or data storage technologies – like:

  • HT superconductors (e.g. cuprates, FeAs-pnictides)
  • Multiferroics (e.g. manganates) and other complex ferro- and antiferromagnetic compounds (e.g. olivines)
  • Ionic conductors (e.g. nickelates)
  • Ferroelectrics (e.g. KDP family)
  • Mixed crystals (e.g. AsSe compounds)
  • Highly absorbing compounds (e.g. with Gd, Sm, Eu)
  • Frustrated magnetic materials (e.g. pyrochlores)
Applications (in general)
  • Structure analysis
  • Hydrogen bonds
  • Static and dynamic disorder
  • Harmonic and anharmonic mean square displacements
  • Twinning
  • Magnetic structure and order
  • Structural and magnetic phase transitions
  • Incommensurate structures
Applications (in detail)
  • Studies of atomic positions and bond distances in compounds with heavy and light elements or elements of similar electron shells
  • Temperature dependent studies for determination of phase transitions
  • Studies of order – disorder phase transitions, e.g. H bonds by determination of anisotropic mean square displacements using large Q range up to sin(Θ)/λ > 1
  • Structure determination of compounds with highly absorbing elements (Gd, Sm, Cd) with short wavelengths
  • Studies on magnetic phase transitions and T dependencies (ferri, ferro and antiferro magnets, multiferroics)
  • Studies on HT superconductors (e.g. cuprates, FeAs pnictides)
  • Sample characterisation by profile analysis
  • Determination of sample orientation, e.g. for preparation of experiments on three axes instruments
  • Presentation of fundamentals of crystallography and structure analysis for education
Sample Environment
  • Closed cycle cryostat (2 K – RT)
  • Mirror furnace (RT – 1500 K)
  • Micro furnace (RT – 500 K)
  • Uniaxial pressure cell (from PUMA)
Technical Data

Beam-tube

  • SR9B (hot source)
  • Flux at sample 1.4·107 cm-2s-1 (λ ≈ 1.17 Å)
  • Gain by hot source × 10 (λ ≈ 0.6 Å)

Wavelength

MGe(311)Cu(220)Ge(422)Cu(420)
20°0.5030.4430.4080.280
40°1.1680.8700.7930.552
50°1.4431.0790.9930.680

Q-range

MGe(311)Cu(220)Ge(422)Cu(420)
20°1.461.952.123.09
40°0.740.991.091.57
50°0.600.800.871.27

Optical components

  • Single detector optimized for small wavelengths (sensitivity >90% at 0.3 Å)
  • Analyzer PG(002); optional for studies of purely elastic scattering and background suppression
  • Neutron filters for suppression of λ/2- or λ/3-contamination of the monochromatized beam

Instrument Scientists

Dr. Martin Meven
Phone: +49.(0)89.289.14727
E-Mail:

Dr. Andrew Sazonov
Phone: +49.(0)89.289.11764
E-Mail:

HEIDI
Phone: +49.(0)89.289.14828

Operated by

Logo RWTH_AIXTal

Gallery

HEiDi
HEiDi
© W. Schürmann, TUM
FWHM
FWHM

Figure 1: FWHM of reflections from a Si sample measured with a wavelength of 0.87 Å using the Cu (220) monochromator.

MLZ is a cooperation between:

Technische Universität München> Technische Universität MünchenHelmholtz-Zentrum Geesthacht> Helmholtz-Zentrum GeesthachtForschungszentrum Jülich> Forschungszentrum Jülich