Atomic Structure and Property Correlation in Pulsed Laser Deposited High -Tc Films

1998 ◽  
Vol 526 ◽  
Author(s):  
R. Kalyanaraman ◽  
S. Oktyabrsky ◽  
K. Jagannadham ◽  
J. Narayan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Boundaries ◽  
Atomic Structure ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Structure And Property ◽  
Transmission Electron ◽  
Tilt Boundaries ◽  
Z Contrast

AbstractThe atomic structure of grain boundaries in pulsed laser deposited YBCO/MgO thin films have been studied using transmission electron microscopy. The films have perfect texturing with YBCO(001)//MgO(001), giving rise to low-angle [001] tilt boundaries from the grains with the c-axis normal to substrate surface. Low angle grain boundaries have been found to be aligned preferentially along (100) and (110) interface planes. The energy of (110) boundary planes described by an alternating array of [100] and [010] dislocation is found to be comparable to the energy of a (100) boundary. The existence of these split dislocations is shown to further reduce the theoretical current densities of these boundaries indicating that (110) boundaries carry less current as compared to (100) boundaries of the same misorientation angle. Further, Z-contrast transmission electron microscopy of a 42° asymmetric high-angle grain boundary of YBCO shows evidence for the existence of boundary fragments and a reduced atomic density along the boundary plane

Diffusion, Migration and the Atomic Structure of some Grain Boundaries

1985 ◽  
Vol 57 ◽  
Author(s):  
W. Krakow ◽  
D. A. Smith
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Grain Boundary ◽  
Atomic Structure ◽  
Boundary Diffusion ◽  
Transmission Electron ◽  
Diffusion Migration ◽  
Tilt Boundaries ◽  
And Migration

AbstractThe atomic structure of representative tilt boundaries in gold has been determined by high resolution transmission electron microscopy. Characteristic and varying regions of decreased density and coordination have been identified and related to mechanisms of grain boundary diffusion and migration

Atomic Structure of Si-SiO2 Interface

1997 ◽  
Vol 3 (S2) ◽  
pp. 459-460
Author(s):  
G. Duscher ◽  
F. Banhart ◽  
H. Müllejans ◽  
S.J. Pennycook ◽  
M. Rühle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atomic Structure ◽  
Phase Contrast ◽  
Thermally Grown Oxide ◽  
Interface Roughness ◽  
Spatial Difference ◽  
Contrast Imaging ◽  
Transmission Electron ◽  
Z Contrast

Investigations of the atomic structure of Si-SiO2 interfaces have mostly been performed with high resolution transmission electron microscopy. However, the interpretation of the phase contrast in the amorphous phase at the interface is not unique. While Ourmazd et al. concluded on a crystalline phase at the Si-SiO2 interface, Akatsu and Ohdomari attributed the same contrast to an interface roughness parallel to the incident electrons.We investigated the Si-SiO2 interface by studying the ELNES of the O-K edge with the spatial difference technique with a dedicated STEM with l00kV (VG HB501 UX). Also the interface was studied by Z-contrast imaging with a 300 kV dedicated STEM (VG HB603 U). Silicon wafers (110) were first thermally oxidised to produce a SiO2 layer. The thermally grown oxide was used as a substrate for liquid phase epitaxy of silicon, given two {111} Si-SiO2 interfaces in the sample grown by two different techniques (see fig. 1).

Structure of Low- And High-Angle Grain Boundaries In YBCO/MgO Films

1998 ◽  
Vol 4 (S2) ◽  
pp. 676-677
Author(s):  
S. Oktyabrsky ◽  
R. Kalyanaraman ◽  
K. Jagannadham ◽  
J. Narayan
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Grain Boundaries ◽  
Atomic Structure ◽  
Boundary Plane ◽  
Dislocation Model ◽  
High Angle ◽  
Transmission Electron

Grain boundaries (GBs) in laser deposited YB2Cu3O7-δ/MgO(001) thin films have been investigated by high-resolution transmission electron microscopy (TEM) and scanning TEM (STEM). We report both statistics and atomic structure of low-angle and high-angle [001] tilt grain boundaries resulting from almost perfect c-axis textured YBCO films.Atomic structure of low-angle GBs was analyzed using a dislocation model. These boundaries have been found to be aligned primarily along (100) and (110) interface planes. For (100) boundary plane, the GB consists of a periodic array of [100] dislocations (Fig.l). For (110) boundary plane, the array is also periodic but every [110] dislocation is split by ∼ 1.5 nm into two [100] and [010] dislocations (Fig.2). We have calculated energy of various configurations and shown that the energy of the (110) boundary with dissociated dislocations is comparable to that of (100) boundary, which explains the coexistence of (100) and (110) interface facets along the boundary.

Ion thinning of integrated circuit transverse specimens for transmission electron microscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1426-1427
Author(s):  
F. Shaapur
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Integrated Circuit ◽  
Substrate Surface ◽  
Homogeneous Material ◽  
Material System ◽  
Ion Milling ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Motion Profile

Non-uniform ion-thinning of heterogenous material structures has constituted a fundamental difficulty in preparation of specimens for transmission electron microscopy (TEM). A variety of corrective procedures have been developed and reported for reducing or eliminating the effect. Some of these techniques are applicable to any non-homogeneous material system and others only to unidirectionalfy heterogeneous samples. Recently, a procedure of the latter type has been developed which is mainly based on a new motion profile for the specimen rotation during ion-milling. This motion profile consists of reversing partial revolutions (RPR) within a fixed sector which is centered around a direction perpendicular to the specimen heterogeneity axis. The ion-milling results obtained through this technique, as studied on a number of thin film cross-sectional TEM (XTEM) specimens, have proved to be superior to those produced via other procedures.XTEM specimens from integrated circuit (IC) devices essentially form a complex unidirectional nonhomogeneous structure. The presence of a variety of mostly lateral features at different levels along the substrate surface (consisting of conductors, semiconductors, and insulators) generally cause non-uniform results if ion-thinned conventionally.

Microstructure of SrTiO3 Thin Films as Single Layer and Incorporated in Yba2Cu3O7-x/SrTiO3 Multilayers

1995 ◽  
Vol 401 ◽  
Author(s):  
L. Ryen ◽  
E. Olssoni ◽  
L. D. Madsen ◽  
C. N. L. Johnson ◽  
X. Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Lattice Mismatch ◽  
Single Layer ◽  
Transmission Electron ◽  
Tilt Boundaries ◽  
Interfacial Dislocations ◽  
The Individual ◽  
Film Substrate

AbstractEpitaxial single layer (001) SrTiO3 films and an epitaxial Yba2Cu3O7-x/SrTiO3 multilayer were dc and rf sputtered on (110)rhombohedral LaAIO3 substrates. The microstructure of the films was characterised using transmission electron microscopy. The single layer SrTiO3 films exhibited different columnar morphologies. The column boundaries were due to the lattice mismatch between film and substrate. The boundaries were associated with interfacial dislocations at the film/substrate interface, where the dislocations relaxed the strain in the a, b plane. The columns consisted of individual subgrains. These subgrains were misoriented with respect to each other, with different in-plane orientations and different tilts of the (001) planes. The subgrain boundaries were antiphase or tilt boundaries.The individual layers of the Yba2Cu3O7-x/SrTiO3 multilayer were relatively uniform. A distortion of the SrTiO3 unit cell of 0.9% in the ‘001’ direction and a Sr/Ti ratio of 0.62±0.04 was observed, both in correspondence with the single layer SrTiO3 films. Areas with different tilt of the (001)-planes were also present, within each individual SrTiO3 layer.

Dislocations and stacking faults in stainless steel

1957 ◽  
Vol 240 (1223) ◽  
pp. 524-538 ◽  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stainless Steel ◽  
Grain Boundaries ◽  
Stacking Faults ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Thin Sections ◽  
Partial Dislocations ◽  
Transmission Electron

Further experiments by transmission electron microscopy on thin sections of stainless steel deformed by small amounts have enabled extended dislocations to be observed directly. The arrangement and motion of whole and partial dislocations have been followed in detail. Many of the dislocations are found to have piled up against grain boundaries. Other observations include the formation of wide stacking faults, the interaction of dislocations with twin boundaries, and the formation of dislocations at thin edges of the foils. An estimate is made of the stacking-fault energy from a consideration of the stresses present, and the properties of the dislocations are found to be in agreement with those expected from a metal of low stacking-fault energy.

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