Structure-property relationships in ferroelectrics extend over several length scales from the individual unit cell to the macroscopic device, and with dynamics spanning a broad temporal domain. Characterizing the multi-scale structural origin of electric field-induced polarization reversal and strain in ferroelectrics is an ongoing challenge that so far has obscured its fundamental behaviour. By utilizing small intensity differences between Friedel pairs due to resonant scattering, we demonstrate a time-resolved X-ray diffraction technique for directly and simultaneously measuring both lattice strain and, for the first time, polarization reversal during in-situ electrical perturbation. This technique is demonstrated for BaTiO3-BiZn0.5Ti0.5O3 (BT-BZT) polycrystalline ferroelectrics, a prototypical lead-free piezoelectric with an ambiguous switching mechanism. This combines the benefits of spectroscopic and diffraction-based measurements into a single and robust technique with time resolution down to the ns scale, opening a new door to in-situ structure-property characterization that probes the full extent of the ferroelectric behaviour.

Different polymorphs of rasburicase, a recombinant urate oxidase enzyme (Uox) from Aspergillus flavus, were obtained as a series of polycrystalline precipitates. Different crystallization protocols were followed in which the salt type, pH and polyethylene glycol 8000 (PEG 8000) concentration were varied. The related crystalline phases were characterized by means of high-resolution synchrotron X-ray powder diffraction. In all cases, Uox complexed with the inhibitor 8-azaxanthine (AZA) was not altered from its robust orthorhombic I222 phase by variation of any of the factors listed above. However, in the absence of AZA during crystallization ligand-free Uox was significantly affected by the type of salt, resulting in different crystal forms for the four salts tested: sodium chloride, potassium chloride, ammonium chloride and ammonium sulfate. Remarkable alterations of some of these phases were observed upon gradual increase of the exposure time of the sample to the synchrotron beam in addition to variation of the PEG 8000 concentration. When Uox was crystallized in Tris buffer or pure water in the absence of salt, a distinct polymorph of orthorhombic symmetry (P2(1)2(1)2) was obtained that was associated with significantly altered lattice dimensions in comparison to a previously reported isosymmetrical structure. The latter form of Uox exhibits enhanced stability to variation of pH and PEG 8000 concentration accompanied by minor modifications of the unit-cell dimensions in the ranges under study. Accurate lattice parameters were extracted for all crystalline phases. This study reveals the rich phase diagram of Uox, a protein of high pharmaceutical importance, which is associated with an enhanced degree of polymorphism. The outcome of our analysis verifies previously reported results as well as demonstrating polymorphs that have altered unit-cell dimensions with respect to known structural models.

Through a solid-state reaction, a practically phase pure powder of Ba3 V2 S4 O3 was obtained. The crystal structure was confirmed by X-ray single-crystal and synchrotron X-ray powder diffraction (P63 , a=10.1620(2), c=5.93212(1) Å). X-ray absorption spectroscopy, in conjunction with multiplet calculations, clearly describes the vanadium in charge-disproportionated V(III) S6 and V(V) SO3 coordinations. The compound is shown to be a strongly correlated Mott insulator, which contradicts previous predictions. Magnetic and specific heat measurements suggest dominant antiferromagnetic spin interactions concomitant with a weak residual ferromagnetic component, and that intrinsic geometric frustration prevents long-range order from evolving.

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Following Phase 2 of the upgrade of the ESRF in which the storage ring was replaced by a new low-emittance ring along with many other facility upgrades, the status of ID22, the high-resolution powder-diffraction beamline, is described. The beamline has an in-vacuum undulator as source providing X-rays in the range 6–75 keV. ID22's principle characteristics include very high angular resolution as a result of the highly collimated and monochromatic beam, coupled with a 13-channel Si 111 multi-analyser stage between the sample and a Dectris Eiger2 X 2M-W CdTe pixel detector. The detector's axial resolution allows recorded 2θ values to be automatically corrected for the effects of axial divergence, resulting in narrower and more-symmetric peaks compared with the previous fixed-axial-slit arrangement. The axial acceptance can also be increased with increasing diffraction angle, thus simultaneously improving the statistical quality of high-angle data. A complementary Perkin Elmer XRD1611 medical-imaging detector is available for faster, lower-resolution data, often used at photon energies of 60–70 keV for pair-distribution function analysis, although this is also possible in high-resolution mode by scanning up to 120° 2θ at 35 keV. There are various sample environments, allowing sample temperatures from 4 K to 1600°C, a capillary cell for non-corrosive gas atmospheres in the range 0–100 bar, and a sample-changing robot that can accommodate 75 capillary samples compatible with the temperature range 80 K to 950°C.