Investigation of Potential Diffusion Barriers Between YBa2Cu3O7-x and Silicon

1989 ◽  
Vol 169 ◽  
Author(s):  
A. Lubig ◽  
Ch. Buchal ◽  
W. Zander ◽  
B. Stritzker
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Noble Metals ◽  
High Temperature Superconductors ◽  
Superconducting Films ◽  
Diffusion Barriers ◽  
Surface Roughening ◽  
Strong Reaction ◽  
Zero Resistance ◽  
Potential Diffusion

AbstractThin films of ZrO2, BaF2, and noble metals on TiN have been examined by RBS as potential diffusion barriers between Si(100) substrates and high-temperature superconductors. As best result so far, a buffer layer of 260 nm ZrO2 enabled the growth of a 230 nm film of YBa2Cu3O7-x, which had been deposited by laser ablation. The relatively low zero resistance temperature of about 60 K may result from some interdiffusion between YBaCuO components and the ZrO2 layer or from holes in the film. A 520 nm BaF2 layer was able to prevent Si outdiffusion towards the surface, when exposed to an oxidizing ambient at typical YBa2Cu3O7-x deposition temperatures between 750 and 800°C. A strong reaction between YBaCuO components and BaF2, however, resulted in non-superconducting films. At high temperatures in oxidizing ambient the noble metal/TiN/Si samples suffered severely from oxidation and surface roughening.

Raman studies of reactive DC-magnetron sputtered thin films of YBaCuO on MgO

1989 ◽  
Vol 4 (6) ◽  
pp. 1312-1319 ◽  
Author(s):  
K. C. Sheng ◽  
S. J. Lee ◽  
Y. H. Shen ◽  
X. K. Wang ◽  
E. D. Rippert ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Critical Temperature ◽  
Impurity Content ◽  
Superconducting Films ◽  
Annealing Process ◽  
Rapid Thermal Annealing Process ◽  
Zero Resistance ◽  
Thermal Annealing Process

Raman spectroscopy was employed to study Y–Ba–Cu–O films prepared by multilayer, reactive sputtering from separate Y, Cu, and Ba0.5Cu0.5 targets. A set of films having the composition YxBa2CuyOz with 0.7 < x < 1.8 and 2.8 < y < 3.5 and critical temperature with zero resistance, Tc(R = 0), ranging from 25 to 90 K was studied with the Raman technique. The correlation between Raman data and critical temperature, Tc, was investigated. This technique provides important information concerning the film crystallinity, homogencity, and impurity content (including other phases) which is useful in judging the quality of high Tc superconducting films. We also found that the rapid thermal annealing process is a very efficient way to reduce chemical reactions between the film and the substrate.

Study of Thin Films of High Temperature Superconductors Based on YBaCuO by EPMA

2000 ◽  
Vol 132 (2-4) ◽  
pp. 365-375 ◽  
Author(s):  
Vladimir V. Tretyakov ◽  
Sergey V. Kazakov ◽  
Alexander V. Bobyl ◽  
Samuil G. Konnikov
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
High Temperature Superconductors

Raman scattering from sputtered films of YBa2Cu3Oy

1988 ◽  
Vol 66 (8) ◽  
pp. 695-699 ◽  
Author(s):  
J. Chrzanowski ◽  
J. C. Irwin ◽  
R. R. Parsons ◽  
P. J. Mulhern
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Magnetron Sputtering ◽  
Raman Scattering ◽  
Oxygen Content ◽  
High Temperature Superconductor ◽  
Superconducting Films ◽  
Vibrational Modes ◽  
Dc Magnetron Sputtering ◽  
Sputtered Films

Thin films of the high-temperature superconductor YBa2Cu3Oy have been deposited on Al2O3 and MgO substrates by dc magnetron sputtering. Raman-scattering experiments have been carried out on these films at various temperatures. The results of these experiments have been used to estimate the amount of impurity phases in the films, to characterize the actual superconducting films, and to test for any preferential orientation within the film. Vibrational modes of the superconductor were found at 148, 226, and 338 cm−1 in both sets of films, at 446 and 491 cm−1 in the Al2O3 films, and at 441 and 500 cm−1 in the MgO films. The measured frequencies of the highest energy modes have been used to determine the oxygen content of the films.

Spin Injection Into YBa2Cu3Ox Films

2003 ◽  
Vol 17 (10n12) ◽  
pp. 491-504
Author(s):  
P. Mikheenko ◽  
M. D. Allsworth ◽  
R. Chakalov ◽  
M. S. Colclough ◽  
C. M. Muirhead
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Spin Injection ◽  
High Temperature Superconductors ◽  
Surface Current ◽  
Current Gain ◽  
Measurable Effect ◽  
Colossal Magnetoresistive ◽  
Spin Polarized ◽  
20 Nm

We report a range of experiments designed to test the efficacy of spin polarized injection from colossal magnetoresistive material (CMR) into high temperature superconductors (HTS). These include traditional transport measurements, studies of CMR/YBCO contacts, measurements of penetration depth and studies of the effect of spin-injection on the critical state of square thin films and rings. We have used pulsed currents to minimize heating and have made comparisons with the non-magnetic homologue of CMR LaNiO3. Our experiments provide evidence that there is a measurable effect, but that it is small and mainly confined to 10–20 nm of the YBCO surface. Current gain of about 0.2 has been observed.

Growth of Complex Epitaxial Multi-Component Oxide Thin Films and Heterostructures with Strong Anisotropy

2011 ◽  
Vol 1368 ◽  
Author(s):  
Kazuhiro Endo ◽  
Petre Badica ◽  
Hidehito Nanto ◽  
Yoshinori Takei ◽  
Shunichi Arisawa ◽  
...  
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Growth Mechanism ◽  
High Temperature Superconductors ◽  
Stability Domain ◽  
Significant Progress ◽  
Strong Anisotropy ◽  
Mocvd Growth ◽  
Film Substrate ◽  
Substrate Film

ABSTRACTWe briefly review our data on MOCVD growth problems of sandwich stacked heterostructures based on Bi-Sr-Ca-Cu-O and YBa2Cu3O7 high temperature superconductors. Non-superconducting layers were (Ca, Sr)CuO2, (Ca, Ba)CuO2 and Bi4Ti3O12. Structures were with c-axis normal or inclined with about 45° vs. the surface of the substrate. Film-substrate lattice relationship, growth mechanism and the resulting morphology controlling roughness and uniformity, stability domain of the phases and inter diffusion are all important aspects toward significant progress in the field. Our analysis indicates that requirements are more severe for non-c-axis heterostructures, and suggest some ideas for further improvements.

Interfaces in high-temperature superconductors

1992 ◽  
Vol 50 (1) ◽  
pp. 234-235
Author(s):  
K.L. Merkle ◽  
Y. Gao
Keyword(s):  
High Temperature ◽  
Critical Current ◽  
Weak Link ◽  
High Temperature Superconductors ◽  
Atomic Scale ◽  
Bulk Materials ◽  
Practical Applications ◽  
Metallic Contacts ◽  
Zero Resistance ◽  
Interfacial Characteristics

After the discovery of high-temperature superconductors (HTS) five years ago, it soon became apparent that their interfacial characteristics would play an extremely important role in any foreseeable applications of these materials. In recent commercial devices, the weak-link characteristics of grain boundaries (GBs) have in fact been exploited to manufacture Josephson junction SQUIDS. On the other hand, the low critical current density of HTS is a considerable limitation for practical applications of the zero-resistance property, particularly in bulk materials. The weak-link behavior of GBs is largely responsible for this, but other types of interfaces such as those formed by metallic contacts or the interfaces between the substrate and a HTS thin film are also critical to the application of these materials. We shall review here some of the important interface issues that have been addressed by TEM techniques, but shall focus largely on the connection between the critical current (Jc) that can be transported across a grain boundary and its atomic-scale structure and composition.

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