5 research outputs found
Evolution of dislocation microstructure in irradiated Zr alloys determined by X-ray peak profile analysis
Bjurböle L/LL4 ordinary chondrite properties studied by Raman spectroscopy, X-ray diffraction, magnetization measurements and Mössbauer spectroscopy
Bjurbole L/LL4 ordinary chondrite was studied using scanning electron microscopy with energy dispersive spectroscopy, Raman spectroscopy, X-ray diffraction, magnetization measurements and Mossbauer spectroscopy. The phase composition and the relative iron fractions in the iron-bearing phases were determined. The unit cell parameters for olivine, orthopyroxene and clinopyroxene are similar to those observed in the other ordinary chondrites. The higher contents of forsterite and enstatite were detected by Raman spectroscopy. Magnetization measurements showed that the temperature of the ferrimagnetic-paramagnetic phase transition in chromite is around 57 K and the saturation magnetic moment is similar to 7 emu/g. The values of the Fe-57 hyperfine parameters for all components in the Bjurbole Mossbauer spectrum were determined and related to the corresponding iron-bearing phases. The relative iron fractions in Bjurbole and the Fe-57 hyperfine parameters of olivine, orthopyroxene and troilite were compared with the data obtained for the selected L and LL ordinary chondrites. The Fe2+ occupancies of the M1 and M2 sites in silicate crystals were determined using both X-ray diffraction and Mossbauer spectroscopy. Then, the temperatures of equilibrium cation distribution were determined, using two independent techniques, for olivine as 666 K and 850 K, respectively, and for orthopyroxene as 958 K and 1136 K, respectively. Implications of X-ray diffraction, magnetization measurements and Mossbauer spectroscopy data for the classification of the studied Bjurbole material indicate its composition being close to the LL group of ordinary chondrites. (C) 2020 Elsevier B.V. All rights reserved.Peer reviewe
Interdependence of the Thermal Properties and Electronic Structure of Y1Ba2CuxOy (1.5<x<9) Ceramics
Direct Measurement of the Cu Oxidation Number of Cuprate Superconductor Ceramics
The Cu oxidation number in YBa2Cu3O7 has been measured directly by soft X-ray fluorescent spectroscopy both at room temperature and at liquid N2 temperature. The measurements are based on a calibration curve from different Ba-O compounds. The effect of changes in oxidation number above and below the transition temperature and its role in high T(c) superconductivity are discussed