High-resolution electron microscopy of the high-temperature superconductor YBa2Cu3O7

Nature ◽  
1987 ◽  
Vol 327 (6121) ◽  
pp. 400-402 ◽  
Author(s):  
E. A. Hewat ◽  
M. Dupuy ◽  
A. Bourret ◽  
J. J. Capponi ◽  
M. Marezio
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
High Resolution ◽  
High Temperature Superconductor ◽  
High Resolution Electron Microscopy ◽  
Resolution Electron

scholarly journals Microstructure of High Temperature Superconductors of the Perovskite Type

1987 ◽  
Vol 40 (4) ◽  
pp. 547 ◽  
Author(s):  
AF Moodie ◽  
HJ Whitfield
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
High Temperature Superconductor ◽  
High Temperature Superconductors ◽  
High Resolution Electron Microscopy ◽  
Convergent Beam Electron Diffraction ◽  
Beam Electron ◽  
Resolution Electron ◽  
Convergent Beam ◽  
Perovskite Type

Combined high resolution electron microscopy and convergent beam electron diffraction (CBED) of the same areas of crystals of Ba3La3Cu6014 reveals defects of various types including ordinary dislocations and polytypic intergrowths. This latter type is considered to be intimately associated with the performance of this material as a high temperature superconductor ..

High Resolution Electron Microscopy of Sintered Ain

1982 ◽  
Vol 40 ◽  
pp. 546-547
Author(s):  
G. Van Tendeloo ◽  
G. Thomas
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
High Resolution ◽  
Stacking Faults ◽  
High Resolution Electron Microscopy ◽  
Tetrahedral Coordination ◽  
Temperature Behaviour ◽  
Resolution Electron ◽  
Suitable Form ◽  
Metal Ratio

Sialon ceramics are widely studied because of their industrial interest due to their high temperature behaviour. AIN, being one of the edge components, has obtained little attention up until now mainly because it is difficult to prepare in a suitable form; moreover, it is a very poor sintering material. Very little is known about the properties or the exact structure. Recently Komeya and Tsuge succeeded in sintering 90wt% A IN and 10wt% SiO2 at 2100°. All the known tetrahedral A IN polytypes are based on the 2H (wurtzite type) structure where A1 and N are in tetrahedral coordination. When the metal to non-metal ratio deviates from one, different polytypes are formed by creating periodic stacking faults every nth layer.

Comparative Oxidation Studies of Polycrystalline HP and CVD Silicon Carbides by TEM

1991 ◽  
Vol 49 ◽  
pp. 938-939
Author(s):  
J.S. Bow ◽  
M.J. Kim ◽  
R.W. Carpenter
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Reaction Time ◽  
High Resolution ◽  
Oxide Layer ◽  
Crystalline Phase ◽  
High Resolution Electron Microscopy ◽  
Substrate Type ◽  
Resolution Electron ◽  
Silicon Carbides

The excellent oxidation resistance of SiC at high temperature results from formation of a protective SiO2 layer in a strongly oxidizing environment. The oxide layer is often initially amorphous, may transform to a crystalline phase for extended reaction time, especially crystobalite above 1200°C. Our objective is use of high resolution electron microscopy methods to determine the oxide layer microstructure dependence on SiC substrate type, and especially to investigate existence of an intermediate Si-O-C phase between the oxide layer and substrate.

Early Stages of Carbon Segregation and Precipitation in a Σ = 5 (310)[001] Molybdenum Tilt Boundary

2002 ◽  
Vol 8 (4) ◽  
pp. 305-311 ◽  
Author(s):  
Jean-Michel Pénisson ◽  
Maria Bacia
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
High Resolution ◽  
Grain Boundary ◽  
High Resolution Electron Microscopy ◽  
Tilt Boundary ◽  
Resolution Electron ◽  
Boundary Precipitation ◽  
Grain Boundary Precipitation ◽  
Tilt Grain Boundary

A Σ = 5 (310)[001] tilt grain boundary in molybdenum has been annealed at high temperature in the presence of carbon and observed in high-resolution electron microscopy. The carbon is located at the grain boundary in a 1-nm slab. Two different morphologies coexist. The first one is a grain boundary precipitation while the second one can be considered as a segregation.

Structural analysis of the surface-layer protein of spirillum serpens by high-resolution electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 738-739
Author(s):  
W. H. Wu ◽  
R. M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Structural Analysis ◽  
High Resolution ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Surface Layer Protein ◽  
Morphological Unit ◽  
Resolution Electron

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.

Electron microscopy of rabbit FC crystals

1983 ◽  
Vol 41 ◽  
pp. 730-731
Author(s):  
Robert A. Grant ◽  
Laura L. Degn ◽  
Wah Chiu ◽  
John Robinson
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Molecular Replacement ◽  
X Ray ◽  
X Ray Crystallography ◽  
Resolution Electron ◽  
Replacement Technique ◽  
Hydrated Crystal ◽  
Molecular Structure Analysis

Proteolytic digestion of the immunoglobulin IgG with papain cleaves the molecule into an antigen binding fragment, Fab, and a compliment binding fragment, Fc. Structures of intact immunoglobulin, Fab and Fc from various sources have been solved by X-ray crystallography. Rabbit Fc can be crystallized as thin platelets suitable for high resolution electron microscopy. The structure of rabbit Fc can be expected to be similar to the known structure of human Fc, making it an ideal specimen for comparing the X-ray and electron crystallographic techniques and for the application of the molecular replacement technique to electron crystallography. Thin protein crystals embedded in ice diffract to high resolution. A low resolution image of a frozen, hydrated crystal can be expected to have a better contrast than a glucose embedded crystal due to the larger density difference between protein and ice compared to protein and glucose. For these reasons we are using an ice embedding technique to prepare the rabbit Fc crystals for molecular structure analysis by electron microscopy.

High resolution electron microscopy of lanthanum phosphate crystals

1978 ◽  
Vol 36 (1) ◽  
pp. 274-275
Author(s):  
J. C. Wheatley ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
High Resolution ◽  
Petroleum Industry ◽  
High Resolution Electron Microscopy ◽  
Lanthanum Phosphate ◽  
Good Catalyst ◽  
Resolution Electron ◽  
Good Catalytic Activity ◽  
Physical And Chemical

Rare-earth phosphates are of particular interest because of their catalytic properties associated with the hydrolysis of many aromatic chlorides in the petroleum industry. Lanthanum phosphates (LaPO4) which have been doped with small amounts of copper have shown increased catalytic activity (1). However the physical and chemical characteristics of the samples leading to good catalytic activity are not known.Many catalysts are amorphous and thus do not easily lend themselves to methods of investigation which would include electron microscopy. However, the LaPO4, crystals are quite suitable samples for high resolution techniques.The samples used were obtained from William L. Kehl of Gulf Research and Development Company. The electron microscopy was carried out on a JEOL JEM-100B which had been modified for high resolution microscopy (2). Standard high resolution techniques were employed. Three different sample types were observed: 669A-1-5-7 (poor catalyst), H-L-2 (good catalyst) and 27-011 (good catalyst).

Possible applications of fraunhofer holography in high resolution electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 222-223 ◽  
Author(s):  
N. Bonnet ◽  
M. Troyon ◽  
P. Gallion
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Transfer Function ◽  
Radiation Damage ◽  
High Resolution Electron Microscopy ◽  
Far Field ◽  
Field Region ◽  
Crystalline Materials ◽  
Resolution Electron ◽  
The Ideal

Two main problems in high resolution electron microscopy are first, the existence of gaps in the transfer function, and then the difficulty to find complex amplitude of the diffracted wawe from registered intensity. The solution of this second problem is in most cases only intended by the realization of several micrographs in different conditions (defocusing distance, illuminating angle, complementary objective apertures…) which can lead to severe problems of contamination or radiation damage for certain specimens.Fraunhofer holography can in principle solve both problems stated above (1,2). The microscope objective is strongly defocused (far-field region) so that the two diffracted beams do not interfere. The ideal transfer function after reconstruction is then unity and the twin image do not overlap on the reconstructed one.We show some applications of the method and results of preliminary tests.Possible application to the study of cavitiesSmall voids (or gas-filled bubbles) created by irradiation in crystalline materials can be observed near the Scherzer focus, but it is then difficult to extract other informations than the approximated size.

Sign in / Sign up

Export Citation Format

Share Document