High-Field Diffractometer

Instrument for Dichroic Soft X-ray Absorption and Scattering Experiments in High Magnetic Fields

The High-Field Diffractometer is dedicated to both soft-x-ray absorption (XAS) and resonant soft x-ray scattering (RSXS) in magnetic fields up to 7 Tesla and temperatures down to 4 K. This combination of high magnetic fields and low temperatures renders the setup ideal for studying weakly coupled magnetic systems like diluted magnets or single molecular magnets. The unique feature of this instrument is an in-vacuum superconducting coil that can be rotated independently from the sample. It is therefore perfectly suited for XMCD and XMLD experiments in various geometries.

Magnet angles and slits to estimate possible x-ray scattering geometries (courtesy A. Frano).

Magnet angles and slits to estimate possible x-ray scattering geometries (courtesy A. Frano).


Methods

XMCD, XMLD, REXS, Magnetic Scattering

Remote access

depends on experiment - please discuss with Instrument Scientist

Beamline data
Energy range 120 - 2000 eV
Energy resolution 10 000
Flux 1012
Polarisation
  • linear any angle (with restrictions)
  • circular
Focus size (hor. x vert.)
  • focussed beam:
    typically 100 µm x 50 µm
    ultimate 40 µm x 10 µm
  • collimated beam:
    ≤ 1.7 mm x 1.5 mm (depending on apertures)
Phone +49 30 8062 14717
More details UE46_PGM-1
Station data
Temperature range 4 - 350 K
Pressure range < 10-10 mbar
Detector AXUV100 type photodiode
Manipulators x/y/z
Sample holder compatibility Native sample holders
Omicron sample plates
Additional equipment
  • Magnetic Field: 7 Tesla
  • Magnetic Field Geometry: horizontal, rotatable (90 deg.) with respect to sample
  • Scattering Geometry: horizontal
  • Sample rotation: limited, depending on orientation of the magnet
  • Software: SPEC

The High-Field Diffractometer is an endstation for both soft-x-ray absorption (XAS)  and resonant soft x-ray scattering (RSXS) in magnetic fields up to 7 Tesla and temperatures down to 4 K. This combination of high magnetic fields and low temperatures renders the setup ideal for studying weakly coupled magnetic systems like diluted magnets or single molecular magnets. The unique feature of this endstation is an in-vacuum superconducting coil that can be rotated independently from the sample. The station is therefore perfectly suited for XMCD and XMLD experiments in various geometries. The absorption signal is typically measured in the TEY-mode via the sample drain current. Employing continuous mode, a pair of energy-dependent absorption scans with opposite light helicities can be recorded with very high quality within less than 10 minutes. Depending on the sample, noise ratios as low as 10-4 can be achieved. A rotatable photon detector enables to perform dichroism experiments using specular reflectivity, which is often more sensitive to tiny magnetizations at interfaces and less surface sensitive than TEY-mode experiments. The same detector permits RSXS experiments at relevant scattering geometries to study the evolution of electronic ordering phenomena, like charge and orbital ordering in high magnetic fields, being at the heart of many of todays most fascinating macroscopic phenomena in complex oxides. Samples are transferred in a  fast and reliable way from outside vacuum to a sample holder directly attached to a LHe-flow cryostat that provides the base temperatures of 4 K. The endstation is permanently attached to the UE46_PGM1 beamline providing high photon flux between 120eV and 2000 eV and variable photon polarization. The beamline also hosts the XUV Diffractometer, an instrument dedicated to high performance RSXS studies. Both instruments can be used within the same beam time. Beamline and instruments are operated by the Institute Quantum Phenomena in Novel Materials at HZB.

 

Selected Applications

  • Diffraction from complex electronic superstructures (magnetic, charge and orbital order)
  • Magnetization states of single molecular magnets
  • Element-specific magnetic hysteresis loops (switching behavior in heterostructures or alloys, exchange bias)
  • Electronic ground states in crystals