Critical currents and micro-structure in YBa2Cu3O7−δ thin films

1996 ◽  
Vol 46 (S3) ◽  
pp. 1307-1308
Author(s):  
J. C. Martínez ◽  
B. Stäuble-Pümpin ◽  
G. Doornbos ◽  
R. Surdeanu ◽  
B. Dam ◽  
...  
Keyword(s):  
Thin Films ◽  
Critical Currents ◽  
Micro Structure

Influence of micro-structure in the low temperature critical currents of YBa2Cu3O7?? thin films

1996 ◽  
Vol 105 (3-4) ◽  
pp. 1017-1022 ◽  
Author(s):  
J. C. Mart�nez ◽  
B. Dam ◽  
B. St�uble-P�mpin ◽  
G. Doornbos ◽  
R. Surdeanu ◽  
...  
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Critical Currents ◽  
Micro Structure

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).

Microstructure of YBa2Cu3O7-x thin films deposited by dc sputtering

1989 ◽  
Vol 47 ◽  
pp. 172-173
Author(s):  
O. Eibl ◽  
G. Gieres ◽  
H. Behner
Keyword(s):  
Thin Films ◽  
Cross Sections ◽  
Intermediate Layer ◽  
Amorphous State ◽  
Critical Currents ◽  
Dc Sputtering ◽  
State Process ◽  
Diffraction Patterns ◽  
Film Substrate ◽  
Substrate Temperatures

The microstructure of high-Tc YBa2Cu3O7-X thin films deposited by DC-sputtering on SrTiO3 substrates was analysed by TEM. Films were either (i) deposited in the amorphous state at substrate temperatures < 450°C and crystallised by a heat treatment at 900°C (process 1) or (ii) deposited at around 740°C in the crystalline state (process 2). Cross sections were prepared for TEM analyses and are especially useful for studying film substrate interdiffusion (fig.1). Films deposited in process 1 were polycristalline and the grain size was approximately 200 nm. Films were porous and the size of voids was approximately 100 nm. Between the SrTiO3 substrate and the YBa2Cu3Ox film a densly grown crystalline intermediate layer approximately 150 nm thick covered the SrTiO3 substrate. EDX microanalyses showed that the layer consisted of Sr, Ba and Ti, however, did not contain Y and Cu. Crystallites of the layer were carefully tilted in the microscope and diffraction patterns were obtained in five different poles for every crystallite. These patterns were consistent with the phase (Ba1-XSrx)2TiO4. The intermediate layer was most likely formed during the annealing at 900°C. Its formation can be understood as a diffusion of Ba from the amorphously deposited film into the substrate and diffusion of Sr from the substrate into the film. Between the intermediate layer and the surface of the film the film consisted of YBa2Cu3O7-x grains. Films prepared in process 1 had Tc(R=0) close to 90 K, however, critical currents were as low as jc = 104A/cm2 at 77 K.

Fem Simulation of Micro-Rotating-Structures and Their Applications in Measurement of Residual Stresses in Thin Films

1997 ◽  
Vol 505 ◽  
Author(s):  
Xin Zhang ◽  
Tong-Yi Zhang ◽  
Yitshak Zohar
Keyword(s):  
Thin Films ◽  
Residual Stresses ◽  
Fem Simulation ◽  
Sensitivity Factor ◽  
Local Measurement ◽  
Micro Structure ◽  
Micro Raman Spectroscopy ◽  
Before And After ◽  
Polysilicon Films ◽  
Simulation Results

ABSTRACTFEM simulation of micro-rotating-structures was performed for local measurement of residual stresses in thin films. A sensitivity factor is introduced, studied and tabulated from the simulation results. The residual stress can be evaluated from the rotating deflection, the lengths of rotating and fixed beams, and the sensitivity factor. The micro-structure technique was applied to measure residual stresses in both silicon nitride and polysilicon thin films, before and after rapid thermal annealing (RTA), and further confirmed by wafer curvature method. Residual stresses in polysilicon films at different RTA stages were also characterized by micro-Raman spectroscopy (MRS). The experimental results indicate that micro-rotating-structures indeed have the ability to measure spatially and locally residual stresses in MEMS thin films with appropriate sensitivities.

Asymmetric critical currents of Nb and YBCO thin films for the polarity of the transport current in parallel magnetic fields

1994 ◽  
Vol 235-240 ◽  
pp. 3095-3096
Author(s):  
F. Ichikawa ◽  
T. Nishizaki ◽  
K. Yamabe ◽  
Y. Yamasaki ◽  
T. Fukami ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Fields ◽  
Critical Currents ◽  
Transport Current ◽  
Ybco Thin Films ◽  
Parallel Magnetic Fields

Orientation Dependence of Critical Currents in a-Axis Oriented YBCO Thin Films

1990 ◽  
pp. 535-538
Author(s):  
X. K. Wang ◽  
D. X. Li ◽  
S. N. Song ◽  
J. Q. Zheng ◽  
R. P. H. Chang ◽  
...  
Keyword(s):  
Thin Films ◽  
Critical Currents ◽  
Orientation Dependence ◽  
Ybco Thin Films

Effect of geometry on the critical currents of thin films

1994 ◽  
Vol 49 (2) ◽  
pp. 1274-1288 ◽  
Author(s):  
G. Stejic ◽  
A. Gurevich ◽  
E. Kadyrov ◽  
D. Christen ◽  
R. Joynt ◽  
...  
Keyword(s):  
Thin Films ◽  
Critical Currents

Critical currents in oxygen-implanted YBa2Cu3O7−σ thin films under magnetic and electrostatic fields

1993 ◽  
Vol 214 (1-2) ◽  
pp. 127-132 ◽  
Author(s):  
Yu.V. Gomeniuk ◽  
V.Z. Lozovski ◽  
V.S. Lysenko ◽  
I.P. Tyagulski
Keyword(s):  
Thin Films ◽  
Critical Currents ◽  
Electrostatic Fields

Lorentz-force dependence of transport critical currents and anisotropic pinning properties in YBa2Cu3O7−δ single-crystalline thin films

1993 ◽  
Vol 204 (3-4) ◽  
pp. 305-314 ◽  
Author(s):  
Terukazu Nishizaki ◽  
Fusao Ichikawa ◽  
Takeshi Fukami ◽  
Takafumi Aomine ◽  
Takahito Terashima ◽  
...  
Keyword(s):  
Thin Films ◽  
Lorentz Force ◽  
Critical Currents ◽  
Single Crystalline ◽  
Pinning Properties
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