Phase slippage in a magnetic field at intra- and intergranular Josephson junctions in high-Tc superconductors

1990 ◽  
Vol 170 (3-4) ◽  
pp. 222-230 ◽  
Author(s):  
G.B. Smith ◽  
K.-H. Müller ◽  
C. Andrikidis ◽  
S.W. Filipczuk ◽  
J.M. Bell ◽  
...  
1988 ◽  
Vol 02 (05) ◽  
pp. 1113-1120
Author(s):  
A. G. Lebed

It's shown, that I − V characteristics of the epitaxial films[1] and unusual magnetic properties of the single crystals[2] may be attributed to the forming on the defects of the plural Josephson junctions. We have given the estimations of the dielectric gap, of the transparence of the corresponding energy barriers and the characteristic distance between them. It's studied the surface superconductivity in the magnetic field. We have marked, that non-trivial boundary condition for High-Tc superconductors[3] lead to the positive curvature on dependence Hc 3 (T) .


1998 ◽  
Vol 12 (29n31) ◽  
pp. 3288-3291
Author(s):  
I. Kirschner ◽  
R. Laiho ◽  
A. C. Bódi ◽  
E. Lähderanta ◽  
I. Vajda

As is shown, thermally assisted vortex motion can come into being in high-T c superconductors due to the applied temperature gradient. Its behavior strongly depends on the local and global microstructure of the samples, moreover on the temperature and magnetic field. Investigation of the density, size and intensity of the pinning centers of specimens leads to the conclusion that the higher homogeneity immediately weakens and the lower one strenghtens the pinning, thus the former promotes and the latter impedes the vortex motion. The non-equilibrium experimental technique together with a.c. susceptibility measurements render possible the direct determination of the velocity of vortices. Depending on the actual microstructural state of samples it has the values between 6 × 10-2 mm/s and 18 × 10-2 mm/s in the case of Y-Ba-Cu-O specimens investigated.


1992 ◽  
Vol 06 (05) ◽  
pp. 265-272 ◽  
Author(s):  
K. SUGAWARA ◽  
T. SUGIMOTO ◽  
D.J. BAAR ◽  
Y. SHIOHARA ◽  
S. TANAKA

Non-resonant microwave absorption (NRMA) studies have been done for Bi-Sr-Ca-Cu-O (BSCCO) films with thicknesses of 30 Å and 15 Å fabricated on MgO substrate by MOCVD. For the latter two kinds of samples have been fabricated: BSCCO/MgO and BiOx/BSCCO/MgO . NRMA signals have been detected up to about 70–75 K for all the samples. The lower critical magnetic field H c1 * of the 30 Å film was severely increased by the application of a magnetic field of several kGauss, whereas it is almost unaffected in the case of 15 Å films. H c1 * increases but the signal intensity decreases with increasing temperature for all the 30 Å and 15 Å samples. The temperature dependence of the intensity is quite different from that of thicker films (100 Å and 350 Å), in which the intensity vs. temperature relation has a peak (or peaks) at particular temperature(s).


1997 ◽  
Vol 277 (3-4) ◽  
pp. 196-202 ◽  
Author(s):  
S. Aukkaravittayapan ◽  
P.J. King ◽  
Yu.I. Latyshev ◽  
R.M. Bowley

1991 ◽  
Vol 05 (09) ◽  
pp. 667-674 ◽  
Author(s):  
K. SUGAWARA ◽  
T. SUGIMOTO ◽  
K. YASUIKE ◽  
D.J. BAAR ◽  
Y. SHIOHARA ◽  
...  

Non-resonant microwave absorption as a function of temperature and magnetic field has been studied in a Bi-Sr-Ca-Cu-O film prepared by MOCVD. A maximum in the absorption as a function of temperature was observed at approximately 60 K. An average Josephson loop diameter of about 0.9~1.5 microns was inferred from the experimental results. The absorption was found to depend on the angle of the film plane relative to the applied field.


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