We propose two improvements to the microstructural modeling in Rietveld refinement. The first is the model that yields the complete texture-weighted strain and stress tensors as a function of crystallite orientations, as well as the average values of macroscopic strain and stress tensors for all Laue classes. Implementation in the Rietveld refinement program can be made through the set of refin...

The paper addresses requirements for achieving Rietveld phase composition analysis (PCA) accuracy in the vicinity of 1% by weight with particular reference to scale factor precision. It is proposed from a statistical analysis that the target for scale factor estimated standard deviation (esd) should be in the vicinity of 0.2% relative, with additional targets being assumed for the ZMV factors, ...

The procedure for the quantitative phase analysis using the whole-powder-pattern decomposition method has been applied to ten-component mixtures of synthesized ceramic materials and a five-component mixture of natural products. Average deviations of the calculated weight fractions of respective phases from those prepared in mixing were within 1 weight percent (wt.%), and they were smaller than ...

We report on the residual stresses in amorphous shape memory polymers reinforced with SiC particles. After 50% compression of the composite material at 25 °C, the SiC particles exhibit a compressive stress, which is almost completely released during heated recovery at 120 °C. The residual stresses in SiC hexagonal (6H) phase were estimated through the average change of the unit-cell volume. Lat...

We have prepared polycrystalline samples of the trimer Ir oxide BaIrO3 with face-shared Ir3O12 trimers, and have investigated the origin of the phase transition at 182 K by measuring resistivity, thermopower, magnetization and synchrotron X-ray diffraction. We propose a possible electronic model and transition mechanism, starting from a localized electron picture on the basis of the Rietveld re...

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...

We discuss the impact of strong absorption for thermal neutrons on data analysis and compare absorption corrections in the GSAS and MAUD Rietveld codes for texture and structural parameter refinement. Diffraction data were collected on the neutron powder diffractometer HIPPO at LANSCE from dysprosium and erbium, which are moderate to strong absorbers for thermal neutrons with absorption cross-s...

Superstructure orthorhombicII (OII) phase in polycrystalline samples of YBCOx was observed by using synchrotron in-situ high resolution powder diffraction (HRPD) techniques at 300˚C. Rietveld method (RM) refinement was employed to analyse the collected diffraction data under proper oxygen partial pressure atmospheres. Our study indicates that by oxygen uptake, the samples undergo structural pha...