The performance characteristics of a new synchrotron x-ray powder diffraction beamline (I11) at the Diamond Light Source are presented. Using an in-vacuum undulator for photon production and deploying simple x-ray optics centered around a double-crystal monochromator and a pair of harmonic rejection mirrors, a high brightness and low bandpass x-ray beam is delivered at the sample. To provide fast data collection, 45 Si(111) analyzing crystals and detectors are installed onto a large and high precision diffractometer. High resolution powder diffraction data from standard reference materials of Si, alpha-quartz, and LaB6 are used to characterize instrumental performance.

Synthesis and characterization of nanosized ferrites from the thermolysis of strontium and barium tris(succinato)ferrate(III) precursors J. Appl. Phys. 109, 07B510 (2011); 10.1063/1.3537949On magnetic properties and domain structure of strontium ferrite particles A series of strontium ferrate compositions ranging from SrFe02.7 to SrFeOa.n have been produced by equilibration at oxygen pressures ranging from 0.2 to 855 atm. The stoichiometric composition SrFeOa.n exhibits a simple cubic perovskite structure (a=3.850 A). Ceramic disks of this material are conductive (p""lQ-a {l.cm) and their temperature dependence is characteristic of metallic conduction. Magnetic measurements indicate that SrFeOs.o is antiferromagnetic below 130 o K. With increasing oxygen deficiency, specimens show increased cell constants and eventually tetragonal distortion. Decrease in the Neel temperature and increased resistivity accompany these changes. 4 H. Wantanabe, J.

Identification of the active species in electrocatalysts toward hydrogen evolution reaction (HER) is of great significance for the development of the catalytic industry; however, it is still the subject of considerable controversy. Herein, we applied operando synchrotron X-ray powder diffraction (SXRD) in the NiSe 2 electrocatalyst system, and an in situ phase transformation from cubic NiSe 2 to hexagonal NiSe was revealed. The NiSe phase showed an enhanced catalytic activity. Operando Raman spectroscopy verified the decomposition of NiSe 2 during HER. Theoretical calculations suggested that the charge transfers from the Se site to Ni site during this evolution process, leading to an increased conductivity and a shifting up of d-band center, which is attributed to the enhanced activity. The generated NiSe phase acts as the "real" active species. Our work unravels the underlying phase transition of the electrocatalyst on reductive conditions in alkaline medium and highlights the significance of identifying the intrinsic active sites under realistic reaction conditions.

The commissioning and performance characterization of a position-sensitive detector designed for fast X-ray powder diffraction experiments on beamline I11 at Diamond Light Source are described. The detecting elements comprise 18 detector-readout modules of MYTHEN-II silicon strip technology tiled to provide 90° coverage in 2θ. The modules are located in a rigid housing custom designed at Diamond with control of the device fully integrated into the beamline data acquisition environment. The detector is mounted on the I11 three-circle powder diffractometer to provide an intrinsic resolution of Δ2θ approximately equal to 0.004°. The results of commissioning and performance measurements using reference samples (Si and AgI) are presented, along with new results from scientific experiments selected to demonstrate the suitability of this facility for powder diffraction experiments where conventional angle scanning is too slow to capture rapid structural changes. The real-time dehydrogenation of MgH(2), a potential hydrogen storage compound, is investigated along with ultrafast high-throughput measurements to determine the crystallite quality of different samples of the metastable carbonate phase vaterite (CaCO(3)) precipitated and stabilized in the presence of amino acid molecules in a biomimetic synthesis process.

Two series of manganate phases have been prepared and their magnetic properties measured. The first series consists, in addition to CaMn0 3 , of three phases having layered structures. In these, tetravalent magnanese ions are contained in single or multiple perovskite layers which are separated from each other by nonmagnetic calcium-oxygen layers. Magnetic exchange of the type Mn 4+ -0-Mn 4+ is disrupted between layers, and decreased Neel temperatures were expected to result. In a second series of phases, the size of of the CaMnOs unit cell was increased by partial substitution of strontium for calcium. Increased separation of manganese ions produced by this means was expected to reduce Neel temperatures. However, contrary to these expectations, Neel temperatures remained approximately constant for the first series of phases and increased for the second.

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A new capability designed for high‐throughput (HT) structural analysis using the synchrotron powder diffraction beamline (I11) at Diamond Light Source is reported. With a high‐brightness X‐ray beam, multi‐analyser detectors and fast data‐acquisition procedures, high‐quality diffraction data can be collected at a speed of ∼15–30 min per powder pattern for good crystalline materials. Fast sample changing at a rate of a few seconds per specimen is achieved with a robotic arm and pre‐loaded capillary specimens on a multi‐tray carousel (200‐sample capacity). Additional equipment, such as an automatic powder‐loading machine and a pre‐alignment jig for the sample capillaries, is available to reduce preparation time. For demonstration purposes, the first results presented here are those from standard reference powders of Si, TiO2 and TiO2/Si mixtures, obtained by analysing the data using Le Bail (instrumental calibration) and Rietveld refinements (quantitative agreement within 1%). The HT hardware was then used to study the structural phase evolution of a library of 31 La4Ni3−xFexO10 heterometallic ceramic powders in less than 1 d. The powders were generated from a single heat treatment (at 1348 K in air for 12 h) of nanoceramic oxide co‐precipitate precursors, made using a newly developed HT synthesis robot. Crystallographic details (symmetry and lattice parameters) were obtained as a function of Fe concentration. The results revealed that this approach was able to produce a pure Ruddlesden–Popper‐type phase with an iron content of up to x = 0.5, significantly higher than has been achieved previously using more conventional synthesis routes and thus demonstrating the power of using the HT approach.