The Electronic Structure, Magnetism and Dynamics (EMD) Group was formed in 2015 and includes the beamlines ID12 (Circular Polarisation), ID20 (Inelastic X-ray scattering I), ID26 (X-ray Absorption and Emission Spectroscopy), ID28 (Inelastic X-ray scattering II) and ID32 (Soft X-ray Spectroscopy). Research performed at these beamlines covers all fields of natural sciences and has a common theme that all beamlines apply spectroscopy to study excited states of matter. Excellent facilities for X-ray absorption spectroscopy are also available at CRG beamlines and this chapter therefore includes some highlights of work performed at BM08 (LISA), BM20 (ROBL), BM26 (DUBBLE) and BM28 (XMaS). We realised that a common forum to present scientific results and discuss instrumentation would be of great benefit and the ESRF now organises public seminars that cover either experimental techniques such as spectroscopy and high pressure or research fields such as magnetism and catalysis. All users are invited to attend the meetings when visiting the ESRF and are encouraged to present their work.

The first phase of the ESRF Upgrade Programme was completed in 2015 and the past months have been particularly exciting for the team of ID32 and the UPBL7 project. The XMCD branch started taking users at the end of 2014. Many groups have used the branch with several very interesting projects being carried out and now the first publications are starting to appear. The sample preparation facility allows UHV preparation of samples. There is a chamber for metal evaporation with LEED and Auger (CMA) diagnostic tools and a separate chamber for molecule evaporation with a MCP-LEED. All the chambers are interconnected also allowing samples to be characterised by an STM. The superconducting high-field magnet 9 Tesla / 4 Tesla (along/perpendicular to the beam) with a low temperature sample probe is ideal for XMCD and XMLD experiments under UHV conditions (see the article from Willers et al.).

The RIXS branch of ID32 started its commissioning in May 2015 with the medium resolution setup. The day one resolution aims were rapidly achieved at the copper L edge: 50-55 meV combined energy bandwidth. The high resolution branch started commissioning in November and achieved a combined bandwidth of 30-35 meV at the copper L edge, already close to the ultimate aim of the project. In addition, the flexibility given by the 5 axis sample goniometer and the continuous rotation of the scattering arm (50-150 degrees scattering angle) is opening up new experimental possibilities which will hopefully be exploited in the coming year. First tests of the RIXS polarimeter have shown that the concept works well although the instrument still needs to be fully commissioned in the coming months (see Braicovich et al. and Minola et al.).

ID20 (UPBL6) entered its second year of full user operation in 2015. The beamline currently holds the world record in energy resolution at the Ir L3 edge, an achievement that attracts many groups interested in the physics of iridates. The high flux combined with a small focal spot size and high energy resolution has enabled new research in particular in high pressure IXS experiments. The large solid angle of the X-ray Raman scattering (XRS) instrument on ID20 has accelerated data acquisition such that time-resolved studies with sub-minute resolution are now possible using this photon-hungry technique. Inkinen et al. monitored the chemical reaction of cinnamic acid with both time (30 seconds) and spatial (50 µm) resolution. They measured C K-edge spectra using XRS and show the effect of dimerisation. The experimental data are nicely supported by calculations of the spectra. Diffuse magnetic scattering with energy resolution was used by Chun et al. to better disentangle the elastic and inelastic scattering response of Na2IrO3. This provides insights into the bond-directional nature of magnetic correlations in this material and supports a magnetic model with dominant Kitaev-type interaction.

An important milestone was reached at ID26 in collaboration with the Crystal Analyser Laboratory (CAL) and the EcoX partnership when a new type of spherical analyser was tested. This new analyser provides a 4-times larger solid angle without degrading the energy resolution. The increased detection efficiency allows samples to be measured with absorber concentrations of a few ppm and accelerates the data acquisition which is particularly important for in situ studies.

The two highlights from ID26 presented in this chapter address the charge transfer after optical excitation in Au/TiO2 nanoparticles (Amidani et al.) and the mechanism for removal of NOx by selective catalytic reduction in vehicle exhaust gases (Günter et al.).

The experimental station at ID12 that is dedicated to X-ray magnetic circular dichroism at low temperatures (down to 2 K) and high magnetic field (up to 17 Tesla) has become a unique experimental platform for basic research on magnetism and the workhorse for XMCD measurements. Two examples in this chapter illustrate its outstanding performance. A long-standing question concerning the modelling of the complex structure of 5f electrons that give rise to the magnetic properties of actinides was addressed by Magnani et al. The second example by Badía-Romano et al. demonstrates how element-selective magnetisation curves probed with XMCD can be used to unravel the mechanism of magnetic interactions in “butterfly” {Fe3LnO2} molecules.

Beamline ID28 upgraded the multi-element low noise detector of the IXS spectrometer. CdTe is now employed that can be used at ambient temperature instead of Peltier cooled silicon. This migration brings the advantages of a more compact design and a more sustainable detector technology, as CdTe is widely used. In the first highlight from ID28, Antonangeli et al. show how combined measurements of density and sound velocity on both body-centered cubic (bcc) and fcc iron as a function of temperature and pressure lead to a revised model of the Moon’s metallic core. A study of the elastic properties of an out-of-equilibrium glass as a function of its age is presented in a second highlight by Pogna et al. The authors conclude that conventional wisdom claiming that glass ceases to flow at a finite temperature could be wrong.

P. Glatzel