The new neutron time-of-flight (TOF) diffractometer HIPPO (High-Pressure-Preferred Orientation) at LANSCE (Los Alamos Neutron Science Center) is described and results for quantitative texture analysis of a standard sample are discussed. HIPPO overcomes the problem of weak neutron scattering intensities by taking advantage of the improved source at LANSCE, a short flight path (9m) and a novel th...

According to the Rietveld refinements and X-ray absorption studies at the Ru K-edge, it is found that three compounds La2BRuOg (B=Li, Mg, and Zn) are monoclinic with space group of P21/n, and that the mthenium ions with two oxidation states +IV (d4) and +~(d3) are stabilized in an octahedral site of oxide lattices. A correlation is obtained between absorption edge position and the oxidation sta...

This paper presents a method of reducing the X-ray diffraction data collection time, while maintaining high data quality, suitable for Rietveld refinement. The approach taken here is that phases in general show peak broadening as well as a loss of intensity with increasing 2-theta. Thus, by splitting the full analyzed 2-theta range into regions and adjusting the step-size and counting time to a...

The solid-state method was used to synthesize single phase potassium-sodium niobate (KNN) co-doped with the La3+-Mn4+ and Eu3+-Fe3+ ion pairs. Structural determination of all studied solid solutions was accomplished by XRD and Rietveld refinement method. Electron paramagnetic resonance (EPR) studies were performed to determine the oxidation state of paramagnetic centers. Optical spectroscopy me...

Nanostructured Ni2As2O7 semiconductor samples were synthesized by a solid state method among As2O3 and Ni(NO3)2.6H2O raw materials at 650 °C (S1) and 750 °C (S2) as reaction temperatures. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique and F...

— The crystal structure of K2TiSi3O9•H2O has been solved ab initio from X-ray powder data. The unit cell is orthorhombic (space group P212121, Z = 4) with cell dimensions a = 7.1362(2) Å, b = 9.9084(3) Å, c = 12.9414(4) Å, V = 915.07 Å. The structural model was obtained from direct methods using 455 integrated intensities. The Rietveld refinement converged to final Bragg and profile indicators ...

Symmetry modes provide an alternative method to describe crystal structures. Using the fact that many crystal structures can be described as a distorted version of a higher symmetric parent structure, the traditional atomic positions, occupancies or lattice parameters are no longer used. Instead, all structural features are described applying symmetry modes. This can be of particular interest i...

Department of Physics, Shanghai University, Shanghai 200444, People’s Republic of China, Shanghai Key Laboratory of High-Temperature Superconductors, Shanghai 200444, People’s Republic of China, Department of Physics, California Institute of Technology, Pasadena, CA 91125, USA, National Laboratory for Superconductivity, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, People’s...