Preparation and Superconducting Properties of Melt-Processed YBCO Bulk by Controlling Oxygen Partial Pressure

1998 ◽  
pp. 657-660 ◽  
Author(s):  
Shuichi Iwata ◽  
Shigeo Nagaya ◽  
Hiroshi Ikuta ◽  
Uichiro Mizutani
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Superconducting Properties ◽  
Ybco Bulk

Resistivity measurement of an a-axis-oriented YBa2Cu3O7–δ thin film at 450-650 °C

1993 ◽  
Vol 8 (4) ◽  
pp. 705-708 ◽  
Author(s):  
Toshio Usui ◽  
Akira Oishi ◽  
Hidekazu Teshima ◽  
Kazumi Ohata ◽  
Tadataka Morishita
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Ybco Film ◽  
Resistivity Measurement ◽  
Ambient Atmosphere ◽  
Reversible Change ◽  
Superconducting Properties ◽  
Ybco Thin Film

Resistivity measurement of an a-axis-oriented YBa2Cu3O7-δ (YBCO) thin film was carried out in a stream of O2/Ar mixtures at 450–650 °C. Rapidly reversible change in the resistivity of the YBCO film was observed as a function of the oxygen partial pressure in the ambient atmosphere due to the oxygen in-/out-diffusion in the YBCO film. Resistivity measurement of YBCO thin films at higher temperatures of 450–650 °C was found to be quite effective to predict the influence of fabricating processes on the superconducting properties of YBCO films.

Formation of Superconducting La2−xSrxCaCu2O6−δ Ceramic with Application of O2-HIP Technique

1991 ◽  
Vol 251 ◽  
Author(s):  
Kiyoshi Oshima ◽  
Yuichi Watanabe ◽  
Masasuke Takata ◽  
Kozo Ishizaki
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Strong Correlation ◽  
Hot Isostatic Pressing ◽  
Lattice Parameters ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Isostatic Pressing ◽  
Diffraction Patterns

ABSTRACTSuperconducting La2−xSrxCaCu2O6−δ ceramics (x=0−0.6) were prepared with application of the oxygen-hot-isostatic pressing (O2-HIP) technique. The Tc of various samples was found to depend on both the Sr content and the applied oxygen partial pressure in the HIP treatment. The maximum Tc onset of 50K was observed for samples of the composition x=0.3 and 0.4 HIPped at 1050°C under 60atm oxygen partial pressure, and x=0.1 and 0.2 HIPped at 1050°C under 400atm oxygen partial pressure, respectively. From the analysis of x-ray diffraction patterns for superconducting substances, it was found that there existed a strong correlation between superconducting properties and the lattice parameters.

Superconductive (Y1−xCax)Ba2Cu4O8 (x = 0.0 and 0.05) ceramics prepared by low and high oxygen partial pressure techniques

1991 ◽  
Vol 6 (1) ◽  
pp. 18-27 ◽  
Author(s):  
Takahiro Wada ◽  
Nobuo Suzuki ◽  
Koji Yamaguchi ◽  
Ataru Ichinose ◽  
Yuji Yaegashi ◽  
...  
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Thermal Analyses ◽  
Annealed Sample ◽  
Crystallographic Structure ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Post Annealing ◽  
Transmission Electron ◽  
Diffraction Patterns

Both YBa2Cu4O8 and (Y0.95Ca0.05)Ba2Cu4O8 were successfully prepared by firing for 160 h at 850 °C and at oxygen partial pressure of 3 atm without using any catalysts. These samples were characterized in terms of the crystallographic structure and thermal and superconducting properties. The x-ray powder diffraction patterns and superconducting properties for these samples were little changed after post-annealing for 6 h at 1070 °C and at oxygen partial pressure of 400 atm. However, when heat-treated at 700 °C in air and then quenched into liquid nitrogen, samples without post-annealing showed broader superconducting transitions than those post-annealed. Actually, the sharpness of the superconducting transition for a post-annealed sample was little affected by quenching. These observations were in agreement with the results of both transmission electron microscopy and thermal analyses.

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