Activation Volume for Inelastic Deformation in Polycrystalline Ag Films at Low Temperatures

1999 ◽  
Vol 594 ◽  
Author(s):  
Mauro J. Kobrinsky ◽  
Carl V. Thompson
Keyword(s):  
Thin Films ◽  
Inelastic Deformation ◽  
Activation Volume ◽  
Metallic Thin Films ◽  
Thermally Activated ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Relaxation Experiments ◽  
The Mean

AbstractThe low temperature (T < 100 °C) inelasticity of polycrystalline Ag thin films on thick substrates has been studied. In-situ Transmission Electron Microscopy and stress-relaxation experiments indicate that thermally-activated glide of dislocations through forest-dislocation obstacles is the dominant inelastic mechanism. Values of the activation volume for inelastic deformation obtained with both experiments are reported. The mean distance between obstacles along the length of moving dislocations was found to be significantly smaller than the thickness of the film and the average grain size, which explains why current models for dislocationmediated plasticity underestimate the strength of thin films. Results from these experiments on Ag are expected to be representative of other metallic thin films (e.g. Cu and Au) on substrates.

Rocking Beam Microarea Diffraction Applied to Metallic thin Films

1976 ◽  
Vol 34 ◽  
pp. 396-397
Author(s):  
R. H. Geiss
Keyword(s):  
Thin Films ◽  
Electron Diffraction ◽  
Small Area ◽  
Objective Lens ◽  
Electron Optics ◽  
Metallic Thin Films ◽  
Transmission Electron Diffraction ◽  
Transmission Electron ◽  
Sample Height ◽  
Scanning Transmission

The theory and practical limitations of micro area scanning transmission electron diffraction (MASTED) will be presented. It has been demonstrated that MASTED patterns of metallic thin films from areas as small as 30 Åin diameter may be obtained with the standard STEM unit available for the Philips 301 TEM. The key to the successful application of MASTED to very small area diffraction is the proper use of the electron optics of the STEM unit. First the objective lens current must be adjusted such that the image of the C2 aperture is quasi-stationary under the action of the rocking beam (obtained with 40-80-160 SEM settings of the P301). Second, the sample must be elevated to coincide with the C2 aperture image and its image also be quasi-stationary. This sample height adjustment must be entirely mechanical after the objective lens current has been fixed in the first step.

Epitaxy and texture analysis of Bi-Sr-Ca-Cu-O thin films on (100) MgO using Transmission Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 68-69
Author(s):  
J. T. Sizemore ◽  
D. G. Schlom ◽  
Z. J. Chen ◽  
J. N. Eckstein ◽  
I. Bozovic ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Critical Currents ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Cell Axis ◽  
Transmission Electron ◽  
Synthesis Procedure

Investigators observe large critical currents for superconducting thin films deposited epitaxially on single crystal substrates. The orientation of these films is often characterized by specifying the unit cell axis that is perpendicular to the substrate. This omits specifying the orientation of the other unit cell axes and grain boundary angles between grains of the thin film. Misorientation between grains of YBa2Cu3O7−δ decreases the critical current, even in those films that are c axis oriented. We presume that these results are similar for bismuth based superconductors and report the epitaxial orientations and textures observed in such films.Thin films of nominally Bi2Sr2CaCu2Ox were deposited on MgO using molecular beam epitaxy (MBE). These films were in situ grown (during growth oxygen was incorporated and the films were not oxygen post-annealed) and shuttering was used to encourage c axis growth. Other papers report the details of the synthesis procedure. The films were characterized using x-ray diffraction (XRD) and transmission electron microscopy (TEM).

Classification of the Modes of Dissociation in Immiscible Cu-Alloy Thin Films

1999 ◽  
Vol 564 ◽  
Author(s):  
K. Barmak ◽  
G. A. Lucadamo ◽  
C. Cabral ◽  
C. Lavoie ◽  
J. M. E. Harper
Keyword(s):  
Thin Films ◽  
Driving Forces ◽  
Texture Evolution ◽  
Substantial Reduction ◽  
Alloying Elements ◽  
X Ray Diffraction ◽  
Cu Alloy ◽  
Transmission Electron ◽  
Evolution Of Microstructure

AbstractWe have found the dissociation behavior of immiscible Cu-alloy thin films to fall into three broad categories that correlate most closely with the form of the Cu-rich end of the binary alloy phase diagrams. The motivation for these studies was to use the energy released by the dissociation of an immiscible alloy, in addition to other driving forces commonly found in thin films and lines, to promote grain growth and texture evolution. In this work, the dissociation behavior of eight dilute (3.3 ± 0.5 at% solute) binary Cu-systems was investigated, with five alloying elements selected from group VB and VIB, two from group VillA, and one from group 1B. These alloying elements are respectively V, Nb, Ta, Cr, Mo, Fe, Ru and Ag. Several experimental techniques, including in situ resistance and stress measurements as well as in situ synchrotron x-ray diffraction, were used to follow the progress of solute precipitation in approximately 500 nm thick films. In addition, transmission electron microscopy was used to investigate the evolution of microstructure of Cu(Ta) and Cu(Ag). For all eight alloys, dissociation occurred upon heating, with the rejection of solute and evolution of microstructure and texture often occurring in multiple steps that range over several hundred degrees between approximately 100 and 900°C. However, in most cases, substantial reduction in resistivity of the films took place at temperatures of interest to metallization schemes, namely below 400°C.

Motion of Crystal/Crystal and Crystal/Amorphous Interfaces

1990 ◽  
Vol 183 ◽  
Author(s):  
J. L. Batstone
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Temperature ◽  
Grain Boundary ◽  
Boundary Motion ◽  
High Temperature Annealing ◽  
Thermally Activated ◽  
Transmission Electron ◽  
Grain Boundary Motion

AbstractMotion of ordered twin/matrix interfaces in films of silicon on sapphire occurs during high temperature annealing. This process is shown to be thermally activated and is analogous to grain boundary motion. Motion of amorphous/crystalline interfaces occurs during recrystallization of CoSi2 and NiSi2 from the amorphous phase. In-situ transmission electron microscopy has revealed details of the growth kinetics and interfacial roughness.

Mechanisms of Grain Growth in Free-Standing Nanograined Gold Thin Films

2005 ◽  
Vol 907 ◽  
Author(s):  
J. A. Gregg ◽  
K Hattar ◽  
C H Lei ◽  
I M Robertson
Keyword(s):  
Thin Films ◽  
Grain Growth ◽  
Structural Changes ◽  
Dislocation Slip ◽  
Free Standing ◽  
Transmission Electron ◽  
Enhanced Properties ◽  
Gold Thin Films ◽  
Annealing Experiments

AbstractRetention of the enhanced properties reported for nanograined metallic systems requires that the nanostructure be insensitive to temperature and deformation. In situ transmission electron microscopy annealing experiments were employed to investigate the structural changes associated with the formation of micron-sized grains in nanograined evaporated gold thin films. This abnormal grain growth occurs randomly throughout the film. Twinning but not dislocation slip occurs in the growing grains until the grain size is in the hundreds of nanometer range. The twins appear to hinder growth and for grain growth to continue the twins must either be annihilated or be able to grow with the grain concurrently.

scholarly journals Donald William Pashley. 21 April 1927 — 16 May 2009

2010 ◽  
Vol 56 ◽  
pp. 317-340 ◽  
Author(s):  
Bruce A. Joyce ◽  
Michael J. Stowell
Keyword(s):  
Thin Films ◽  
Electron Microscope ◽  
Electron Diffraction ◽  
Film Growth ◽  
Epitaxial Thin Films ◽  
Disorder Effects ◽  
Transmission Electron ◽  
Innovative Materials ◽  
Low Dimensional

Donald William (Don) Pashley was one of the most innovative materials scientists of his generation. He was distinguished for his electron diffraction and transmission electron microscope studies of epitaxial thin films, especially for in situ investigations, work that contributed enormously to our understanding of film growth processes. He pioneered the use of moiré patterns to reveal dislocations and other defects. He also made important contributions to long-range disorder effects on semiconductor surfaces and to the structure of low-dimensional semiconductor systems.

Size of pores of Kohn: influence of transpulmonary and vascular pressures

1981 ◽  
Vol 51 (3) ◽  
pp. 739-745 ◽  
Author(s):  
R. W. Mazzone ◽  
S. Kornblau
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Pore Size ◽  
Minimum Diameter ◽  
Transmission Electron ◽  
Zone Ii ◽  
The Mean ◽  
Alveolar Septa ◽  
Collateral Ventilation

We investigated the influence of transpulmonary (Ptp) and vascular pressures on the size of the pores of Kohn in primary alveolar septa. Dogs lungs, perfused and ventilated in situ, were rapidly frozen with Freon 22 in zone II or III conditions following deflation to Ptp of 5, 15, or 25 cmH2O. Frozen samples were freeze-substituted for transmission electron microscopy. Five fields containing at least one pore each were selected randomly from each section of tissue, and the minimum diameter visible in the cut section was measured. For both zone II and III conditions, as Ptp increased, mean pore size increased. The mean pore size under zone III conditions was 1.2015, 1.788, and 2.249 micrometer for Ptp of 5, 15, and 25 cmH2O, respectively. For zone 2 conditions, the corresponding values were 1.1438, 1,8757, and 2.08 micrometer. For both zones II and III, increasing capillary hydrostatic pressure had no significant effect on pore size. The results support the notion that alveolar pores can increase collateral ventilation by dynamically stretching as Ptp increases. Capillary pressure does not influence pore size probably because of collagen fibers, which surround the pore lumen. Presumably, these fibers resist encroachment of capillaries on the pore lumen as vascular pressures increase.

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