Rietveld X-ray Powder Profile Analysis and Electrical Conductivity of Fastion Conducting Gd2(Til-ySny)2O7 Solid Solutions

1996 ◽  
Vol 453 ◽  
Author(s):  
Kevin Eberman ◽  
Per Önnerud ◽  
Tae-Hwan Yu ◽  
Harry L. Tuller ◽  
Bernhardt J. Wuensch
Keyword(s):  
Electrical Conductivity ◽  
Solid Solutions ◽  
Profile Analysis ◽  
Structural Parameters ◽  
Ion Conduction ◽  
X Ray ◽  
Lattice Constants ◽  
Order Of Magnitude ◽  
Fast Ion ◽  
Cation Sites

AbstractThe A3+2B4+2O7 pyrochlores have fast-ion conduction properties that make them attractive candidates for applications in fuel cells. Rietveld powder-profile analysis of x-ray diffraction data has been used to determine structural parameters for Gd2(Ti1-ySny)2O7 solid solutions (y = 0.20, 0.40, 0.60, and 0.80) for correlation with composition-dependence of the specimens' electrical conductivity. In accord with Vegard's law, the lattice constants increase linearly with y as the larger Sn ion replaces Ti4+. The structures in the system remain remarkably ordered in view of the fact that it had been suggested that increasing the average radius of the ions that occupy the B4+ site relative to A3+ drives the system toward a disordered defect-fluorite state. A small but significant increase in mixing of the occupancy of the cation sites was found with increasing y to a maximum of [GdB] = 0.05. We could detect no significant disorder in the anion array. The activation energy and pre-exponential term for oxygen ion conduction were found to increase linearly and exponentially with y, respectively, such that at a given temperature, the ionic conductivity changes by less than an order of magnitude across the system. The behavior is in marked contrast to other systems where the substitution of a larger cation in the B site increases conductivity by up to three orders of magnitude as a consequence of substantial disorder that is introduced in both the cation and anion arrays.

Structure and Conductivity of Iodine-Doped C60 Thin Films

1994 ◽  
Vol 359 ◽  
Author(s):  
Jun Chen ◽  
Haiyan Zhang ◽  
Baoqiong Chen ◽  
Shaoqi Peng ◽  
Ning Ke ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Room Temperature ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
X Ray ◽  
Thermally Activated ◽  
Order Of Magnitude

ABSTRACTWe report here the results of our study on the properties of iodine-doped C60 thin films by IR and optical absorption, X-ray diffraction, and electrical conductivity measurements. The results show that there is no apparent structural change in the iodine-doped samples at room temperature in comparison with that of the undoped films. However, in the electrical conductivity measurements, an increase of more that one order of magnitude in the room temperature conductivity has been observed in the iodine-doped samples. In addition, while the conductivity of the undoped films shows thermally activated temperature dependence, the conductivity of the iodine-doped films was found to be constant over a fairly wide temperature range (from 20°C to 70°C) exhibiting a metallic feature.

scholarly journals SYNTHESIS AND ELECTRICAL CONDUCTIVITY OF SOLID SOLUTIONS OF THE SYSTEM RbF-PbF2-SnF2

2019 ◽  
Vol 85 (5) ◽  
pp. 60-68
Author(s):  
Yuliay Pogorenko ◽  
Anatoliy Omel’chuk ◽  
Roman Pshenichny ◽  
Anton Nagornyi
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Temperature Dependence ◽  
Solid Solutions ◽  
Basic Structure ◽  
Elementary Cell ◽  
Initial Structure ◽  
Fluoride Ions ◽  
Temperature Range ◽  
Order Of Magnitude

In the system RbF–PbF2–SnF2 are formed solid solutions of the heterovalent substitution RbxPb0,86‑xSn1,14F4-x (0 < x ≤ 0,2) with structure of β–PbSnF4. At x > 0,2 on the X-ray diffractograms, in addition to the basic structure, additional peaks are recorded that do not correspond to the reflexes of the individual fluorides and can indicate the formation of a mixture of solid solutions of different composition. For single-phase solid solutions, the calculated parameters of the crystal lattice are satisfactorily described by the Vegard rule. The introduction of ions of Rb+ into the initial structure leads to an increase in the parameter a of the elementary cell from 5.967 for x = 0 to 5.970 for x = 0.20. The replacement of a part of leads ions to rubium ions an increase in electrical conductivity compared with β–PbSnF4 and Pb0.86Sn1.14F4. Insignificant substitution (up to 3.0 mol%) of ions Pb2+ at Rb+ at T<500 K per order of magnitude reduces the conductivity of the samples obtained, while the nature of its temperature dependence is similar to the temperature dependence of the conductivity of the sample β-PbSnF4. By replacing 5 mol. % of ions with Pb2+ on Rb+, the fluoride ion conductivity at T> 450 K is higher than the conductivity of the initial sample Pb0,86Sn1,14F4 and at temperatures below 450 K by an order of magnitude smaller. With further increase in the content of RbF the electrical conductivity of the samples increases throughout the temperature range, reaching the maximum values at x≥0.15 (σ573 = 0.34–0.41 S/cm, Ea = 0.16 eV and σ373 = (5.34–8.16)•10-2 S/cm, Ea = 0.48–0.51 eV, respectively). In the general case, the replacement of a part of the ions of Pb2+ with Rb+ to an increase in the electrical conductivity of the samples throughout the temperature range. The activation energy of conductivity with an increase in the content of RbF in the low-temperature region in the general case increases, and at temperatures above 400 K is inversely proportional decreasing. The nature of the dependence of the activation energy on the concentration of the heterovalent substituent and its value indicate that the conductivity of the samples obtained increases with an increase in the vacancies of fluoride ions in the structure of the solid solutions.

X-ray scattering of non-graphitic carbon: an improved method of evaluation

2002 ◽  
Vol 35 (5) ◽  
pp. 624-633 ◽  
Author(s):  
Wilhelm Ruland ◽  
Bernd Smarsly
Keyword(s):  
Profile Analysis ◽  
Structural Parameters ◽  
Wide Angle ◽  
Line Profiles ◽  
Improved Method ◽  
X Ray ◽  
X Ray Scattering ◽  
Fitting Procedures ◽  
Method Of Evaluation ◽  
Ray Scattering

The wide-angle X-ray scattering (WAXS) of non-graphitic carbons shows relatively broad and diffuse interference maxima. In most cases, the corresponding line profiles cannot be separated unambiguously, so that an evaluation using profile analysis is difficult. In these cases, fitting procedures for the total scattering curve are more appropriate. This requires theoretical expressions for all interference maxima with a sufficient number of relevant structural parameters to ensure an acceptable fit. In this paper, such expressions are presented for the (hk) lines (intralayer scattering) and the (00l) lines (interlayer scattering), and the application of these expressions to the evaluation of selected WAXS curves is described. Furthermore, the effects of thermal motion, preferred orientation and Compton scattering are discussed.

X-ray line profile analysis—An ideal tool to quantify structural parameters of nanomaterials

JOM ◽  
2011 ◽  
Vol 63 (7) ◽  
pp. 61-70 ◽  
Author(s):  
Michael B. Kerber ◽  
Michael J. Zehetbauer ◽  
Erhard Schafler ◽  
Florian C. Spieckermann ◽  
Sigrid Bernstorff ◽  
...  
Keyword(s):  
Line Profile ◽  
Profile Analysis ◽  
Structural Parameters ◽  
Line Profile Analysis ◽  
X Ray ◽  
Ideal Tool

Neutron, X-ray and Brillouin scattering studies of rotator phases with fast ion conduction

1981 ◽  
Vol 5 ◽  
pp. 445-447 ◽  
Author(s):  
R. Aronsson ◽  
H.E.G. Knape ◽  
A. Lundén ◽  
L. Nilsson ◽  
L.M. Torell
Keyword(s):  
Brillouin Scattering ◽  
Ion Conduction ◽  
X Ray ◽  
Fast Ion

scholarly journals Synthesis, Crystal Structure Refinement, and Electrical Conductivity of Pb(8−x)Na2Smx(VO4)6O(x/2)

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Tatiana M. Savankova ◽  
Lev G. Akselrud ◽  
Lyudmyla I. Ardanova ◽  
Alexey V. Ignatov ◽  
Eugeni I. Get’man ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Solid Solutions ◽  
Structure Refinement ◽  
Crystal Structure Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Solid solutions of Pb(8−x)Na2Smx(VO4)6O(x/2)were studied using X-ray diffraction analysis including Rietveld refinement and scanning electron microscopy and by measuring their electrical conductivity. Crystal structure of the solid solutions was refined and the solubility region0≤x≤0.2was determined for samarium substitution for lead under the scheme2Pb2++□→2Sm3++O2-. The influence of degree of substitution on the electrical conductivity of solid solutions was established.

scholarly journals Electrical conductivity and conduction mechanisms in (Na0.5Bi0.5TiO3)1−x(BiScO3)x (0.00 ≤ x ≤ 0.25) solid solutions

2018 ◽  
Vol 6 (43) ◽  
pp. 11598-11607 ◽  
Author(s):  
F. Yang ◽  
P. Wu ◽  
D. C. Sinclair
Keyword(s):  
Electrical Conductivity ◽  
Solid Solutions ◽  
Oxygen Vacancies ◽  
Ion Conduction ◽  
Conduction Mechanisms ◽  
Oxide Ion Conduction ◽  
Oxide Ion

Large acceptor ions on B-sites are less effective in trapping oxygen vacancies and consequently less effective to suppress the oxide-ion conduction in NBT.

Non-destructive microstructural analysis with depth resolution: application to seashells

2002 ◽  
Vol 35 (5) ◽  
pp. 594-599 ◽  
Author(s):  
E. Zolotoyabko ◽  
J. P. Quintana
Keyword(s):  
Profile Analysis ◽  
Structural Parameters ◽  
Microstructural Analysis ◽  
Depth Resolution ◽  
Line Profile Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Energy Variable ◽  
Evolution Of Microstructure ◽  
Textured Materials

Energy-variable X-ray diffraction at a synchrotron beamline has been used to control the X-ray penetration depth and thus to study structural parameters in polycrystalline and textured materials with depth resolution. This approach was applied to the investigation of the depth evolution of microstructure in the nacre layer of bivalvia seashells. According to conventional X-ray diffraction and scanning electron microscopy, the nacre layer in the seashells ofAcanthocardia tuberculataunder investigation consists of large [001]-oriented lamellae packed nearly parallel to the inner shell surface. In this paper, attention is focused on the microstructural information that can be extracted from the shapes of diffraction profiles (line profile analysis) measured at X-ray energies that are varied by small steps. Depth dependences of the thickness of the lamellae and the average microstrain fluctuation are revealed.

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