9 5 I H I G H L I G H T S 2 0 2 2
The inelastic scattering spectrometer and diffuse scattering side station on beamline ID28 are running in tandem operation. The beamline is in growing demand by the user community for joint experiments, where diffuse scattering provides the roadmaps for time-consuming inelastic measurements, and inelastic scattering helps to identify the features that are observed in diffuse scattering. The portfolio of sample environments now includes diamond- anvil cells for diffraction and a closed-cycle cryostat for combined diffraction/diffuse scattering studies. The articles in this chapter cover the phonon dispersion curves of black phosphor (page 105) and the mechanical properties of sea urchin spine (page 106).
Beamline ID26 is improving its capabilities in the tender X-ray range by increasing the number of analyser crystals in the tender X-ray spectrometer (TEXS) and by commissioning an operando cell that can be run in the vacuum of the TEXS chamber. The beamline staff, together with their colleagues in the Instrument Support and Development Division, improved the position stability of the beam exiting the double-crystal monochromator. The new beamline control software, BLISS, is now stable, and the data can be directly interfaced with the suite of data reduction tools in DAXS, which is maintained by the Algorithm and Data Analysis (ADA) group. We chose as highlights the work by Elnaggar et al. (page 102) on charge re-ordering in magnetite, and Wissel et al. (page 104) on single-layer nickelates as potential cuprate-like superconductors.
The increase in onsite user visits meant that both the XMCD and the Resonant Inelastic X-ray Scattering (RIXS) branches on ID32 were fully operational. The articles highlighted this year come from the RIXS branch and show examples of how quantum phenomena can be studied using RIXS. The first article deals with fractional spin excitations in cuprates (page 108). The study makes good use of the very high energy resolution available at ID32 and the unique possibility of measuring the polarisation of the scattered photons. The second study deals with Kondo coherence.
It reveals in unprecedented detail how the full manifold of localised f-electron states hybridises with the underlying band structure in the archetypal Kondo metal CePd3 (page 109). This work opens up many new possibilities in the field, in particular because the current work is not limited by the experimental energy resolution, meaning that similar studies are feasible in materials with lower Kondo energy scales or in systems where Kondo dynamics can be tuned by external parameters. Such studies can also be performed on microscopic single crystals not accessible to Inelastic Neutron Scattering, and future studies will benefit from the continuous improvements in brilliance and energy resolution of the RIXS instrument at ID32.
The Sample Environment Unit is fully dedicated to the preparation of user experiments, the design of new setups following requests by the beamline staff, and equipment maintenance. In 2022, the unit prepared and participated in more than 140 user or in-house research experiments. Among the new or ongoing developments are an in-situ cell for X-ray absorption spectroscopy on pellets, a cell for loosely packed powder samples for operando tender X-ray spectroscopy, a continuous flow cell for microcrystals, allowing the flow of a liquid cooled down to liquid nitrogen temperature or heated up to 120°C, and a hydrogen reactor under pressurised hot oil for grazing incidence operando studies of catalysts. Many requests for high temperature (~1350°C) experiments in air without windows are realised by induction heating. Such experiments are becoming routine due to the flexibility of the setup. A new high- throughput setup for powder diffraction has now been commissioned. It features a rack of 66 holders, each containing 16 samples, with each individual sample having its own QR code triggering file naming and online data reduction. Each sample change takes 95 ms and the sample holder change (every 16 samples) takes three seconds.
P. GLATZEL, A. ROGALEV, C. SAHLE, A. BOSAK, N. BROOKES AND Y. WATIER