A custom built high-field superconducting magnet integrated with an in-situ sample preparation system. This end-station is designed for x-ray magnetic circular and linear dichroism experiments (XMCD/XMLD).

High-Field Magnet

This custom built magnet was designed especially for Soft X-ray XMCD and XMLD measurements. The magnetic field of 9 Tesla along the beam direction can be ramped at 8 Tesla per minute, and a magnetic field of 4 Tesla perpendicular to the beam direction can be ramped at 2 Tesla per minute. However, we typically ramp at 3T/min along the beam and 1T/min perpendicular to the beam, though we can adjust the rate depending on the required fields and the experimental need.

The sample is vacuum-mounted onto a LHe variable temperature insert that can reach ~6 K, but should be improved in the near future to ~3K, and can go up to 325K. This insert can be rotated over 360 degrees about the vertical axis. The sample space is ultra-high vacuum (10-10 to 10-11 mbar base pressure with sample at room temperature), obtained by cryo-pumping of the liquid helium can. Absorption spectra can be simultaneously measured in drain current and total fluorescence yield mode, and if requested in transmission.

Sample Preparation

The magnet is connected in ultra-high vacuum to a cluster of chambers for in-situ sample preparation and characterisation. The capabilities of the system can be extended by users who wish to bring their own chambers to prepare samples for their experiment in situ.
 
prep.png
 

Ex-Situ Samples

Thin Films

Molecules & Low Vapour Pressure Materials

  • Load-lock
  • Sputtering
  • Annealing to 500°C
  • Sample Cleaver & Scraper
  • Up to 2 Evaporation Sources
  • Storage of 5 Samples
  • UHV Ports for User Tools
  • Up to 4 Evaporation Sources
  • Wedge Growth
  • Quartz Microbalance Monitor
  • Sputtering
  • Cooling & Annealing
    (< 100 - 2300 K)
  • Gas Dosing
  • Auger Electron Spectroscopy (AES)
  • LEED
  • Up to 4 Evaporation Sources
  • Wedge Growth
  • Quartz Microbalance Monitor
  • Sputtering
  • Cooling & Annealing
    (< 100 - 1500K)
  • Gas Dosing
  • LEED & µA LEED

Omicron VT-STM

User Port

Sample Storage

  • 70 - 300 K
  • STM Tip Preparation Tool
  • In-situ Evaporation
  • Load-lock (standard)
  • Ar glove-box
  • UHV suitcase
  • User Set-ups
  • Up to 20 Samples

Sample Holders

We have developed a range of sample holders in high-purity aluminum or copper. Samples can be glued or clamped down.
A special sample holder using Omicron plates for single crystals is available. Sample size can be anything between 2 mm and 14 mm.
The screws are molybdenum, and Omicron plates used are mostly tantalum, with tungsten or molybdenum plates also available. This is because they must be non-magnetic for use in the HFM

Sample Holder Type 1: Plate Screwed into Shuttle

sample_holders_xmcd.png
 
 

Sample Holder Type 2: Omicron Plate Slid into Shuttle

sample_holders_xmcd_omicron_plates.png
The Omicron plate dimensions are contained within this document - the plate is covered by 1mm at each end when slotted in the holders, thus the effective width of the plate is 16mm (2mm reduced).
 

Sample size

Samples should have a minimum size of 0.7 × 0.05 mm2 (horizontal × vertical). For smaller sizes contact us in advance. Since the beam spot dimensions are adjustable, spot sizes of up to several millimeters are also possible.
 

For more information please contact the beamline staff and/or see the following publication.

The high-field magnet endstation for X-ray magnetic dichroism experiments at ESRF soft X-ray beamline ID32
K. Kummer, A. Fondacaro, E. Jimenez, E. Velez-Fort, A. Amorese, M. Aspbury, F. Yakhou-Harris, P. van der Linden, N. B. Brookes
Journal of Synchrotron Radiation 23,  464 (2016).  DOI