Issues Concerning the Chemical Synthesis of Ceramic Superconducting Coatings in the Bi-Sr-Ca-Cu-O System with High Critical Current Densities.

1991 ◽  
Vol 249 ◽  
Author(s):  
S. J. Golden ◽  
K. J. Vaidya ◽  
T. E. Bloomer ◽  
F. F. Lange ◽  
D. R. Clarke
Keyword(s):  
Thin Films ◽  
Critical Current ◽  
Zero Field ◽  
Superconducting Thin Films ◽  
Ethyl Hexanoate ◽  
X Ray ◽  
Pole Figures ◽  
Oriented Films ◽  
Metalorganic Deposition ◽  
Current Densities

ABSTRACTSuperconducting thin films of the two Cu-layer phase in the Pb-doped Bi- Sr-Ca-Cu-O system have been fabricated on {100} LaAlO3 single crystals by the metalorganic deposition (MOD) from ethyl hexanoate precursors. Some of the major issues pertinent to the synthesis of high quality films have been studied.Thin films of composition Bi1.8Pb0.3Sr1.6CaCu2Ox given heat treatments in air at 850–860 °C for several hours had sharp resistive transitions with a Tc of 85–89 K. The zero-field transport critical current densities were in the range of 1–4×105 A.cm−2 at 77 K and 106 A.cm−2 at 45 K in 200–300 nm thick films. In contrast to caxis oriented films grown on (100) MgO, X-ray pole figures show that the polycrystalline films grown on (100) LaAlO3 are epitaxial, a result confirmed by electron channeling patterns.

Crystallization of Epitaxial Lanthanum Aluminate and Spinel Thin Films Derived from Nitrate Precursors

1994 ◽  
Vol 341 ◽  
Author(s):  
Man Fai Ng ◽  
Michael J. Cima
Keyword(s):  
Thin Films ◽  
Epitaxial Film ◽  
Amorphous Film ◽  
Zero Field ◽  
Epitaxial Thin Films ◽  
Lanthanum Aluminate ◽  
Initial Nucleation ◽  
Metalorganic Deposition ◽  
Current Densities ◽  
Higher Temperature

AbstractBoth lanthanum aluminate (LaAIO 3) and spinel (MgAl2O 4) epitaxial thin films have been deposited on either planar and stepped (100) SrTiO3 single crystal substrates by pyrolysis of mixed nitrate precursors. The precursors pyrolyze initially into amorphous films. Nucleation of lanthanum aluminate and spinel occurs at the filnVsubstrate interface at higher temperature. Crystallization of LaAlO3 on SrTiO3 substrates occurs at approximately 650°C, whereas nucleation occurs at approximately 800'C without lattice-matched substrates. Similarly, latticematched substrates reduce the crystallization temperature of spinel to below 700°C. The epitaxial film grows at the expense of the amorphous film after the initial nucleation at the interface. The rapid growth and volume change due to the crystallization leave behind an epitaxial film with nanoporosity of 15 to 30 nm. Nevertheless, the surfaces of these films have roughness of only 6–9 Å. Ba2Ycu3O7-x films derived from metalorganic deposition of metal trifluoroacetate precursors was deposited on these epitaxial LaAlO3 films on both planar and stepped SrTiO3 substrates. The resultant YBCO films on LaAlO3 film on planar SrTiO3 substrate have critical current densities of > 2 × 106 A/cm2 at 77K and zero field.

X-ray Line Broadening Analysis of Tl-Superconducting Films

1989 ◽  
Vol 33 ◽  
pp. 145-151
Author(s):  
M. O. Eatough ◽  
D. S. Ginley ◽  
B. Morosin
Keyword(s):  
Thin Films ◽  
Superconducting Films ◽  
Electron Beam Evaporation ◽  
Superconducting Thin Films ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Current Densities ◽  
Diffraction Peaks ◽  
Sequential Electron

AbstractSuperconducting thin films (0.3-0.7μm) in the TI-Ca-Ba-Cu-0 system have been prepared on various single crystal substrates by sequential electron beam evaporation followed by appropriate sintering and annealing. Oxygen-annealed films show Tc as high as 110K and critical current densities to 600,000 A/cm2. X-ray diffraction analyses of these films show predominantly the Tl2Ca2Ba2Cu2O10 phase (c-parameter near 36Å), but some also contain up to 50 at% of the Tl2CaBa2Cu2O8 phase (c-parameter near 30Å). The complete absence of hkl reflections other than 00I demonstrates the highly oriented nature of the films as well as the absence of other Tl phases. The diffraction peaks are noticeably broader for the 36Å phase than for the 30Å phase. For a 0.7μm film such broadening is consistent with coherent sizes along the c-axis of 1200 - 1400Å and 500Å, respectively, for the 30Å and 36Å phases, and of strain values near 1.4-1.8 x 10-3 for both phases.

Ba2YCu3O7−x Thin Films with Jc>105 A/cm2 at 77 K Prepared by Metalorganic Deposition at Reduced Oxygen Pressure

1991 ◽  
Vol 249 ◽  
Author(s):  
Robert B. Hallock ◽  
W.E. Rhine ◽  
M.S. Jolly ◽  
MIchael J. Cima
Keyword(s):  
Thin Films ◽  
Spin Coating ◽  
Total Pressure ◽  
Applied Field ◽  
Methanol Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metalorganic Deposition ◽  
Zero Resistance ◽  
Current Densities

ABSTRACTSuperconducting Ba2YCu3O7-x films 0.1-0.2 gim thick were prepared by spin coating a methanol solution of Ba, Y and Cu acrylates on (100)LaAlO3 and firing to 800°C in a total pressure of 1 mm O2. X-ray diffraction showed that these films were epitaxial with the c-axis normal to the substrate. Zero resistance was achieved above 90 K and transport DC critical current densities as high as 125,000 A/cm2 were measured at 77 K in zero applied field.

Textures of laser ablated superconducting thin films of YBa2Cu3O7−δ as a function of deposition temperature

1992 ◽  
Vol 7 (3) ◽  
pp. 549-557 ◽  
Author(s):  
F. Heidelbach ◽  
H-R. Wenk ◽  
R.E. Muenchausen ◽  
S. Foltyn ◽  
N. Nogar ◽  
...  
Keyword(s):  
Thin Films ◽  
Deposition Temperature ◽  
Substrate Surface ◽  
Surface Characteristic ◽  
Film Structure ◽  
Preferred Orientation ◽  
Superconducting Thin Films ◽  
Characteristic Parameters ◽  
X Ray ◽  
Pole Figures

The preferred orientation of a series of laser deposited superconducting thin films of YBa2Cu3O7−δ on LaAlO3 substrate has been examined. X-ray measurements (pole figures, χ-scans, ω-scans, rocking curves) reveal an increasingly strong preferred orientation of the polycrystalline material with c-axes perpendicular to the substrate surface as deposition temperature increases. At low temperatures c-axes are predominantly parallel to the substrate surface. Characteristic parameters of the texture types were derived from those measurements. With higher temperatures twinning on (110) was observed. The different texture types are interpreted in terms of a layered film structure.

Characterization of Epitaxial Superconducting YBacuO Thin Films with Three Different Orientations

1989 ◽  
Vol 169 ◽  
Author(s):  
X.K. Wang ◽  
D.X. Li ◽  
S.N. Song ◽  
J.Q. Zheng ◽  
R.P.H. Chang ◽  
...  
Keyword(s):  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Orientation Dependence ◽  
Zero Field ◽  
Epitaxial Thin Films ◽  
Oriented Film ◽  
Zero Resistance ◽  
Xrd Patterns

AbstractEpitaxial thin films of YBaCuO were prepared by multilayer deposition from Y, Cu, and BaF2 sources with: (1) the a‐axis perpendicular to (100)SrTiO3; (2) the c‐axis perpendicular to (100)SrTiO3; and (3) the [110] axis perpendicular to (110)SrTiO3. XRD patterns as well as SEM and HREM images confirm that the films are highly oriented, essentially epitaxial. Both the a‐axis oriented and the c‐axis oriented films exhibit zero resistance at 91K. The [110] oriented film shows the sharpest transiton with a transition width of IK and zero resistance at 85K. The zero field critical current density, Jc, determined magnetically, is in excess of 107A/cm2 at 4.4K and 1.04 x 106A/cm2 at 77K for the c‐axis oriented film; for the a‐axis oriented film we obtained 6.7 x 106A/cm2 at 4.4K and 1.2 x 105A/cm2 at 77K. The orientation dependence of the critical current density in the basal plane of the a‐axis oriented film was studied. The largest Jc's occur along the in‐plane <100> axes of the substrate.

X-Ray Diffraction Analysis of High Tc Superconducting Thin Films

1989 ◽  
pp. 269-278
Author(s):  
T. C. Huang ◽  
A. Segmüller ◽  
W. Lee ◽  
V. Lee ◽  
D. Bullock ◽  
...  
Keyword(s):  
Thin Films ◽  
Diffraction Analysis ◽  
Superconducting Thin Films ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray
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