Microstructures of Cu- and Y-rich YBa2Cu3O7−x thin films

1990 ◽  
Vol 48 (4) ◽  
pp. 38-39
Author(s):  
A.F. Marshall
Keyword(s):  
Thin Films ◽  
Critical Currents ◽  
Electron Beam Evaporation ◽  
Second Phase ◽  
X Ray Diffraction ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
Defect Microstructure

The defect microstructure of Cu- and Y-rich thin films of the high Tc superconductor YBa2Cu3O7−x (123) is of interest for several reasons. The highest Tc' reported for well-ordered stoichiometric films are typically 90-91 K. Post-annealed Cu- and Y-rich films may exhibit Tc's of 95-96 K. X-ray diffraction showed these non-stoichiometric films to be a highly faulted mixture of the 123 and 248 (Y2Ba4Cu8O16,Tc=80 K) phases. In situ films made by sputtering or electron beam evaporation typically show sharp but depressed Tc's (75-85 K); for our films these values approach 90 K when the films are Cu- and Y-rich. Both post annealed and in situ films exhibit high critical currents on and off stoichiometry; the pinning characteristics, which may be highly influenced by the defect microstructure, are superior for the in situ techniques.Transmission electron microscopy analysis shows that excess Cu and Y can be incorporated both as stacking fault (SF) defects and as second phase precipitates.

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).

FORMATION OF TWO LAYERS IN Pr1-xCaxBa2Cu3O7-y(0≤x≤0.5) THIN FILMS DEPOSITED AT DIFFERENT TEMPERATURES

2000 ◽  
Vol 14 (16) ◽  
pp. 1651-1657
Author(s):  
J. A. DÍAZ ◽  
O. CONTRERAS ◽  
J. M. SIQUEIROS
Keyword(s):  
Thin Films ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Transmission Electron Microscopy Analysis ◽  
X Ray ◽  
Cell Parameters ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
Different Temperatures ◽  
Microscopy Analysis

We have grown epitaxial Pr 1-x Ca x Ba 2 Cu 3 O 7-y(0≤x≤0.5) thin films on SrTiO 3 and Yttrium stabilized zirconia (YSZ) substrates by pulsed laser deposition at different temperatures. X-ray diffraction and transmission electron microscopy analysis revealed epitaxial growth on YSZ substrates for x=0 along the a and c axis directions for T=570° C , where first the film grows oriented along a-axis and afterward, it undergoes a shift in the orientation, growing in the c-axis direction from then on. The cell parameters were c=1.166 nm and a~b=0.386 nm .

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.

High-Quality III-V Nitrides Grown by Metalorganic Chemical Vapor Deposition

1995 ◽  
Vol 395 ◽  
Author(s):  
R.D. Dupuis ◽  
A.L. Holmes ◽  
P.A Grudowski ◽  
K.G. Fertitta ◽  
F.A. Ponce
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
High Quality ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
Metalorganic Chemical

ABSTRACTWe report the growth of high-quality III-V nitride heteroepitaxial films on (0001) sapphire substrates by low-pressure metalorganic chemical vapor deposition (MOCVD). These films have exhibited narrow X-ray diffraction rocking curves with full-width-at-half-maximum values as low as ΔΘ∼37 arc sec. Photoluminescence and transmission electron microscopy analysis further indicate the samples to be of high quality.

Growth and Characterization of (012)- and (001)-Oriented Epitaxial Anatase Thin Films

2006 ◽  
Vol 46 ◽  
pp. 146-151
Author(s):  
Andriy Lotnyk ◽  
Stephan Senz ◽  
Dietrich Hesse
Keyword(s):  
Thin Films ◽  
Cross Section ◽  
Single Phase ◽  
Electron Beam Evaporation ◽  
X Ray Diffraction ◽  
Tio2 Thin Films ◽  
X Ray ◽  
Transmission Electron

Single phase TiO2 thin films of anatase structure have been prepared by reactive electron beam evaporation. Epitaxial (012)- and (001)-oriented anatase films were successfully obtained on (110)- and (100)-oriented SrTiO3 substrates, respectively. X-ray diffraction and cross section transmission electron microscopy investigations revealed a good epitaxial quality of the anatase films grown on the SrTiO3 substrates.

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