Oxygen exchange study in phase transformations of superconducting bismuth cuprates (Pb2212 and Pb2223)

1997 ◽  
Vol 50 (3) ◽  
pp. 401-407 ◽  
Author(s):  
M. Mansori ◽  
C. Favotto ◽  
K. Jardet ◽  
M. Roubin ◽  
A. Sebaoun ◽  
...  
Keyword(s):  
Phase Transformations ◽  
Oxygen Exchange ◽  
Exchange Study ◽  
Bismuth Cuprates

scholarly journals Oxygen exchange kinetics on systematically doped ceria: a pulsed isotope exchange study

2019 ◽  
Vol 7 (38) ◽  
pp. 21854-21866 ◽  
Author(s):  
Maximilian Schaube ◽  
Rotraut Merkle ◽  
Joachim Maier
Keyword(s):  
Exchange Rate ◽  
Isotope Exchange ◽  
Dopant Concentration ◽  
Strong Dependence ◽  
Oxygen Exchange ◽  
Doped Ceria ◽  
Exchange Study ◽  
Redox Active ◽  
Exchange Kinetics

20 systematically doped ceria samples: strong dependence of oxygen exchange rate on dopant concentration, even steeper for redox-active dopants (Pr).

scholarly journals Isotopic Oxygen Exchange Study to Unravel Noble Metal Oxide/Support Interactions: The Case of RuO 2 and IrO 2 Nanoparticles Supported on CeO 2 , TiO 2 and YSZ

ChemCatChem ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2548-2555
Author(s):  
Yasmine M. Hajar ◽  
Antoinette Boreave ◽  
Angel Caravaca ◽  
Philippe Vernoux ◽  
Elena A. Baranova
Keyword(s):  
Metal Oxide ◽  
Noble Metal ◽  
Oxygen Exchange ◽  
Oxide Support ◽  
Exchange Study ◽  
Metal Oxide Support

The use of high-resolution FESEM to study solid-state phase transformations and reactions

1994 ◽  
Vol 52 ◽  
pp. 1028-1029
Author(s):  
P. G. Kotula ◽  
D. D. Erickson ◽  
C. B. Carter
Keyword(s):  
Solid State ◽  
High Resolution ◽  
Phase Transformations ◽  
High Efficiency ◽  
Sol Gel ◽  
Quantitative Information ◽  
Solid State Reactions ◽  
Critical Dimensions ◽  
Backscattered Electrons ◽  
Backscattered Electron

High-resolution field-emission-gun scanning electron microscopy (FESEM) has recently emerged as an extremely powerful method for characterizing the micro- or nanostructure of materials. The development of high efficiency backscattered-electron detectors has increased the resolution attainable with backscattered-electrons to almost that attainable with secondary-electrons. This increased resolution allows backscattered-electron imaging to be utilized to study materials once possible only by TEM. In addition to providing quantitative information, such as critical dimensions, SEM is more statistically representative. That is, the amount of material that can be sampled with SEM for a given measurement is many orders of magnitude greater than that with TEM.In the present work, a Hitachi S-900 FESEM (operating at 5kV) equipped with a high-resolution backscattered electron detector, has been used to study the α-Fe2O3 enhanced or seeded solid-state phase transformations of sol-gel alumina and solid-state reactions in the NiO/α-Al2O3 system. In both cases, a thin-film cross-section approach has been developed to facilitate the investigation. Specifically, the FESEM allows transformed- or reaction-layer thicknesses along interfaces that are millimeters in length to be measured with a resolution of better than 10nm.

The use of transmission and analytical electron microscopy in studying reactions and phase transformations in thin film

1993 ◽  
Vol 51 ◽  
pp. 842-843
Author(s):  
K. Barmak
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Transformations ◽  
Analytical Electron Microscopy ◽  
Ex Situ ◽  
Multilayer Thin Films ◽  
Absolute Concentration ◽  
Analytical Electron ◽  
Deposition Step

Generally, processing of thin films involves several annealing steps in addition to the deposition step. During the annealing steps, diffusion, transformations and reactions take place. In this paper, examples of the use of TEM and AEM for ex situ and in situ studies of reactions and phase transformations in thin films will be presented.The ex situ studies were carried out on Nb/Al multilayer thin films annealed to different stages of reaction. Figure 1 shows a multilayer with dNb = 383 and dAl = 117 nm annealed at 750°C for 4 hours. As can be seen in the micrograph, there are four phases, Nb/Nb3-xAl/Nb2-xAl/NbAl3, present in the film at this stage of the reaction. The composition of each of the four regions marked 1-4 was obtained by EDX analysis. The absolute concentration in each region could not be determined due to the lack of thickness and geometry parameters that were required to make the necessary absorption and fluorescence corrections.

Crystal chemistry of high-Tc superconductors

1990 ◽  
Vol 48 (4) ◽  
pp. 1118-1119
Author(s):  
Maryvonne Hervieu
Keyword(s):  
Oxygen Deficiency ◽  
Large Family ◽  
Copper Oxides ◽  
High Tc Superconductors ◽  
High Tc ◽  
Single Mechanism ◽  
Square Planar ◽  
History Of ◽  
Bismuth Cuprates ◽  
New Compounds

Four years after the discovery of superconductivity at high temperature in the Ba-La-Cu-O system, more than thirty new compounds have been synthesized, which can be classified in six series of copper oxides: La2CuO4 - type oxides, bismuth cuprates, YBa2Cu3O7 family, thallium cuprates, lead cuprates and Nd2CuO4 - type oxides. Despite their quite different specific natures, close relationships allow their structures to be simply described through a single mechanism. The fifth first families can indeed be described as intergrowths of multiple oxygen deficient perovskite slabs with multiple rock salt-type slabs, according to the representation [ACuO3-x]m [AO]n.The n and m values are integer in the parent structures, n varying from 0 to 3 and m from 1 to 4; every member of this large family can thus be symbolized by [m,n]. The oxygen deficient character of the perovskite slabs involves the existence or the co-existence of several types of copper environment: octahedral, pyramidal and square planar.Both mechanisms, oxygen deficiency and intergrowth, are well known to give rise easily to nonstoichiometry phenomena. Numerous and various phenomena have actually been characterized in these cuprates, strongly depending on the thermal history of the samples.

A Transmission Electron Microscopical Investigation of Phase Transformations in TiNi

1980 ◽  
Vol 38 ◽  
pp. 340-341
Author(s):  
P. Moine ◽  
G. M. Michal ◽  
R. Sinclair
Keyword(s):  
Electron Microscopy ◽  
Phase Transformations ◽  
Applied Stress ◽  
Structural Changes ◽  
Microscopical Investigation ◽  
Temperature Range ◽  
Transmission Electron ◽  
Electron Microscopical ◽  
Diffraction Effects ◽  
Microscopy Images

Premartensitic effects in near equiatomic TiNi have been pointed out by several authors(1-5). These include anomalous contrast in electron microscopy images (mottling, striations, etc. ),diffraction effects(diffuse streaks, extra reflections, etc.), a resistivity peak above Ms (temperature at which a perceptible amount of martensite is formed without applied stress). However the structural changes occuring in this temperature range are not well understood. The purpose of this study is to clarify these phenomena.

Resistivity anisotropy and Josephson coupling in lead-substituted bismuth cuprates

1994 ◽  
Vol 4 (11) ◽  
pp. 2249-2257 ◽  
Author(s):  
F.-X. Régi ◽  
J. Schneck ◽  
H. Savary ◽  
R. Mellet ◽  
P. Müller ◽  
...  
Keyword(s):  
Josephson Coupling ◽  
Resistivity Anisotropy ◽  
Bismuth Cuprates

Phase transformations in Pd-and Ni-rich Ti-Pd-Ni alloys

2003 ◽  
Vol 112 ◽  
pp. 1043-1046 ◽  
Author(s):  
M. Nagasako ◽  
M. Nishida
Keyword(s):  
Phase Transformations ◽  
Ni Alloys
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