From meandering to straight grain boundaries: Improving the structures of artificially induced grain boundaries in superconducting YBa2Cu3Oy bicrystals

1997 ◽  
Vol 12 (11) ◽  
pp. 3029-3035 ◽  
Author(s):  
Xiao-Feng Zhang ◽  
Volk R. Todt ◽  
Dean J. Miller
Keyword(s):  
Thin Film ◽  
Grain Boundaries ◽  
Film Deposition ◽  
Ybco Bulk ◽  
Transmission Electron ◽  
Ybco Superconductors ◽  
Film Deposition Rate ◽  
Melt Texture ◽  
Key Aspects ◽  
Misorientation Angles

This paper presents several key aspects of our approach to preparing artificially induced [001] tilt grain boundaries (GB's) with uniform, well-defined structures in YBa2Cu3Oy (YBCO) superconductors. GB structures formed in thin film and bulk bicrystals, respectively, will be compared. In YBCO thin film bicrystals, meandering rather than planar GB's are formed. Using a low film deposition rate has been demonstrated to reduce the magnitude of meander significantly, but complete elimination of the meander has not yet been accomplished. Thus, we have developed a dual-seeded-melt-texture process to produce uniform, planar GB's with controllable misorientation angles in YBCO bulk bicrystals. Transmission electron microscopy (TEM) studies reveal a remarkably planar and simple configuration on different length scales. Such a simple structure allows for an insightful interpretation of transport behavior across individual GB's.

Variation of thin film deposition rate on SS 314 with the variation of gas flow rate using CVD

2011 ◽  
Vol 63 (6) ◽  
pp. 433-439 ◽  
Author(s):  
Mohammad Asaduzzaman Chowdhury ◽  
Dewan Muhammad Nuruzzaman ◽  
Khaled Khalil ◽  
Mohammad Lutfar Rahaman
Keyword(s):  
Thin Film ◽  
Deposition Rate ◽  
Flow Rate ◽  
Gas Flow ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Gas Flow Rate ◽  
Film Deposition Rate

FTIR absorption spectroscopy as a novel method for thin film deposition rate measurement

2013 ◽  
Vol 114 (4) ◽  
pp. 1295-1301
Author(s):  
Thomas Reichenbacher ◽  
Simon Schuetz ◽  
Ilja Stasewitsch ◽  
Stephan Fabig
Keyword(s):  
Thin Film ◽  
Deposition Rate ◽  
Absorption Spectroscopy ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Rate Measurement ◽  
Film Deposition Rate ◽  
Novel Method

Methods in Characterizing the SrTiO3/GaAs Interface

2012 ◽  
Vol 5 (1) ◽  
Author(s):  
T. Cooper ◽  
Q. Qiao ◽  
R.F. Klie
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Gaas Substrate ◽  
Theoretical Calculations ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Transmission Electron ◽  
Significant Interest ◽  
Electron Energy Loss ◽  
Theoretical Results

Characterizing the interface that occurs between a thin-film deposition of SrTiO3 on a GaAs substrate is of significant interest in order to determine the electrical capabilities that may be possible with this type of system. Imaging the interface by using transmission electron microscopy as well as determining important chemical and electrical information by using Electron Energy Loss Spectroscopy (EELS) are critical in determining if the system is actually appropriate for the desired applications. In addition to these experimental calculations, however, it may be useful to determine theoretical calculations in order to confirm and interpret the results. In particular, these may be determined for EELS by using a simulation program called FEFF9, which employs use of full multiple scattering calculations in order to produce these theoretical results.

Transmission Electron Microscopy Study of YBa2Cu3O7-x Thin Film Multilayer Devices

1997 ◽  
Vol 474 ◽  
Author(s):  
M. A. Barnett ◽  
J. S. Abell ◽  
M. Aindow ◽  
N. G. Chew ◽  
P. J. Hirst ◽  
...  
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Boundaries ◽  
Slope Angle ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Base Layer ◽  
Transmission Electron Microscopy Study ◽  
Transmission Electron

ABSTRACTPatterned thin film multilayer structures, consisting of superconducting YBa2Cu3O7-x (YBCO) and insulating PrBa2Cu3O7-x (PrBCO), deposited onto (001) MgO substrates by electron beam co-evaporation, have been examined using Transmission Electron Microscopy (TEM). It is shown that PrBCO films grown over 30° steps in YBCO layers are free of tilt-grain boundaries. The PrBCO is c-oriented everywhere and shows pronounced faceting on the steps. Strain contrast features are present where the PrBCO has to adapt to large variations in the slope angle of the underlying YBCO layer. However, tilt-grain boundaries in YBCO or PrBCO layers are nucleated when depositing over small MgO steps formed by unintentional milling into the substrate. It is shown that grain boundaries associated with milled steps on MgO can be eliminated by the use of a PrBCO buffer layer beneath the superconducting base layer.

Control of meandering grain boundary configurations in YBa2Cu3Oy bicrystal thin films based on deposition rate

1996 ◽  
Vol 11 (10) ◽  
pp. 2440-2449 ◽  
Author(s):  
X. F. Zhang ◽  
D. J. Miller ◽  
J. Talvacchio
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Grain Boundary ◽  
Deposition Rate ◽  
Three Dimensional ◽  
Film Deposition ◽  
Island Growth ◽  
Ybco Films ◽  
Transmission Electron ◽  
Film Deposition Rate

Changing the film deposition rate is shown to be one way to influence the meandering configurations of grain boundaries (GB's) formed in YBa2Cu3Oy (YBCO) bicrystal thin films. The magnitude and wavelength of the meander in YBCO films deposited at two different rates have been characterized by transmission electron microscopy (TEM) and statistically quantified. It has been found that the meander becomes more uniform and considerably less rough in films deposited at lower rates compared to that observed in films deposited at higher rates. A mechanism for the formation of the meandering GB is proposed based on heterogeneous nucleation and three-dimensional (3D) island growth together with overgrowth of the YBCO films across the substrate grain boundary. The different island sizes and tendency for overgrowth induced by changing the film deposition rate are believed to play important roles in controlling the meandering GB configuration. The possible effects of meandering configurations on transport properties are discussed.

Microstructures and transport properties: A comparison between grain boundaries artificially produced in YBa2Cu3Ov bicrystal thin films and bulk crystals

1996 ◽  
Vol 54 ◽  
pp. 728-729
Author(s):  
X.F. Zhang ◽  
V.R. Todt ◽  
D.J. Miller ◽  
M. St. Louis-Weber ◽  
J. Talvacchio
Keyword(s):  
Thin Films ◽  
Transport Properties ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Bulk Crystals ◽  
Transmission Electron ◽  
Electromagnetic Measurements ◽  
Global Transport ◽  
Film Deposition Rate ◽  
Microstructural Studies

In order to establish the link between grain boundary (GB) structures and transport properties in superconducting materials, electromagnetic measurements and detailed microstructural studies of carefully prepared GBs are required. Frequently, artificially induced GBs prepared by thin film deposition onto bicrystal substrates are used for such studies. Recently, transmission electron microscopy (TEM) studies have revealed a meandering configuration for GBs in YBa2Cu3Oy (YBCO) thin films grown on [001] tilt SrTiO3 bicrystal substrates (Fig. la). The deviation of the meandering GBs away from the underlying substrate GBs varies from a few tens to hundreds of nanometers. We have demonstrated that the magnitude of the meander in terms of amplitude and wavelength can be reduced by lowering the film deposition rate. The meandering GBs were shown to consist of various straight facets which are a few tens to hundreds of nanometers in length. It is possible that the various segments have very different current transport behavior due to a variable misfit dislocation density. Thus, an unambiguous correlation between the microstructure and global transport properties is difficult to attain.

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