Determination of the crystal structure and charge density of (Ba0.5Sr0.5)(Co0.8Fe0.2)O2.33 by Rietveld refinement and maximum entropy method analysis

Study of charge density and crystal structure of (La0.75Sr0.25)MnO3.00 and (Ba0.5Sr0.5)(Co0.8Fe0.2)O2.33−δ at 500–900K by in situ synchrotron X-ray diffraction

“…At present, the neutron diffraction for the time of flight-type is the best way to separate the contributions of site occupancy and U iso ; however, it is impossible to calculate charge density from neutron diffraction data. In our previous study, we reported that U iso of O1(4c) and O2(8d) sites in BSCF and the O site in LSM was about 0.01 Å 2 [38]. Considering the previous study and this study, U iso of the O2(8d) site in BSCF and the O site in LSM did not show temperature dependence at 300-900 K. The temperature independence indicates the atomic disorder reported by Guenter et al [40], and we speculate that these sites in BSCF and LSM have only small thermal vibrations.…”

“…Note: The oxygen site occupancies (*) refined by the Rietveld analysis of the ND, iodometry [38,39], and XANES spectra at 300 K were fixed for each temperature.…”

“…Crystal structures determined by SR-XRD at 500-900 K Fig. 3 shows the results of Rietveld refinements of the observed and calculated profiles as well as the structural parameters of LSM and BSCF at 500 K, respectively, using the rhombohedral and orthorhombic models given in Table 2 [38,39]. Table 3 show the structural parameters and reliability factors of LSM and BSCF at 500-900 K, respectively.…”

“…The reliability factors of LSM at 500-900 K used after the Rietveld refinements were the reliability weighted pattern factors (R wp ) = 0.0377-0.0441, the goodness of fit factors (S) (=R wp /R e : the reliability expected factor) = 1.31-1.56, and the reliability Bragg factor (R B ) = 0.0309-0.0337. For the first refinement, the BSCF crystal structure was successfully determined by considering a perovskite structure with the space group Pnma to adopt the split atom model for cation sites [38,39]; the oxygen site occupancies refined by Rietveld refinement of neutron diffraction measurements at 300 K that constrained the total oxygen constant to 2.33 by iodometry were fixed for each temperature [38,39]. The reliability factors of BSCF were R wp = 0.0285-0.0293, S = 2.12-2.21, and R B = 0.0313-0.0359 at 500-900 K after the Rietveld refinements.…”

Micro- and macro-indentation behaviour of Ba0.5Sr0.5Co0.8Fe0.2O3−d perovskite

“…6,7,12 By now also several reports are available on the thermal expansion behaviour and electrical conductivity of BSCF of different compositional variation. [13][14][15] Some recent works 16,17 have reported in great detail the charge density profile, atomic -isotropic displacement parameters and conductivity of BSCF based on data from synchrotron X-ray diffraction measurements, permitting an identification of the detailed temperature dependent oxygen transport mechanisms. Recently, Liu et al 18 have studied the variation of crystal structure and chemical state of BSCF using XRD and X-ray photoelectron spectroscopy (XPS).…”