THE DIFFUSION OF THE VORTICES IN HIGH Tc THIN FILM MICROBRIDGES: MODEL AND RESULTS

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3626-3634
Author(s):  
P. BERNSTEIN ◽  
M. PANNETIER ◽  
Ph. LECOEUR ◽  
T. D. DOAN ◽  
J. F. HAMET
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Vortex Motion ◽  
Bias Current ◽  
Vortex Pinning ◽  
Superconducting Thin Film ◽  
High Tc ◽  
Current Flows ◽  
Creep Regime ◽  
Physical Quantities

We have previously proposed a model for the flux creep regime of the vortices in superconducting thin film microbridges in which a bias current flows. In the first part of the paper this model is summarized and we show how physical quantities which are relevant to estimate the importance of vortex pinning in the samples can be determined. Then, the effect of a low applied magnetic field on the modulation of the critical current of the microbridges is discussed and we show how this type of measurements can give additionnal information on the vortex motion in the samples and allows to determine their superconducting thickness and penetration depth as a function of temperature.

Lorentz microscopy observation of vortex dynamics due to transport current

1995 ◽  
Vol 53 ◽  
pp. 366-367
Author(s):  
T. Yoshida ◽  
H. Kasai ◽  
J.E. Bonevich ◽  
T. Matsuda ◽  
A. Tonomura
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Vortex Dynamics ◽  
Chemical Etching ◽  
Vortex Motion ◽  
Transport Current ◽  
Vortex Pinning ◽  
Resistive State ◽  
Microscopy Observation ◽  
Lorentz Microscopy

At present, Lorentz microscopy is the only one method to visualize individual vortices in superconductors and observe their motion in real time. Using this technique, we have investigated the fascinating vortex dynamics in superconductors, niobium and BSCCO. And recently we applied it to investigate current driven vortex motion.The vortices are driven by the Lorentz force due to the transport current, and begin to move. This couses the vortex to dissipate the energy i.e., causes the resistive state in the superconductor. Therefore to clarify the vortex motion is important especially in the relation with vortex pinning.The sample we examined was niobium thin film, which was single-crystallized by annealing and thinned by chemical etching. It was put in the low temperature specimen stage specially developed for the vortex observation, which was installed in 350 kV FE-TEM based Hitachi H-9000.We observed current driven vortex motion in the temperature (T) range from 4.5 K to Tc = 9.25 K and in a (externally applied) magnetic field (B) up to 100 Gauss.

Resistive Behavior of High Tc Superconducting Thin Film in Magnetic Field

1990 ◽  
pp. 687-690 ◽  
Author(s):  
T. Matsuura ◽  
S. Tanaka ◽  
K. Harada ◽  
H. Itozaki ◽  
S. Yazu
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Superconducting Thin Film ◽  
High Tc

scholarly journals Moving Pearl Vortices in Thin-Film Superconductors

2021 ◽  
Vol 6 (1) ◽  
pp. 4
Author(s):  
Vladimir Kogan ◽  
Norio Nakagawa
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Time Dependent ◽  
Superconducting Thin Film ◽  
Self Energy ◽  
London Equation ◽  
The Magnetic Field

The magnetic field hz of a moving Pearl vortex in a superconducting thin-film in (x,y) plane is studied with the help of the time-dependent London equation. It is found that for a vortex at the origin moving in +x direction, hz(x,y) is suppressed in front of the vortex, x>0, and enhanced behind (x<0). The distribution asymmetry is proportional to the velocity and to the conductivity of normal quasiparticles. The vortex self-energy and the interaction of two moving vortices are evaluated.

In-situ laser preparation of high-Tc superconducting thin film at 450°-550° C

1991 ◽  
Author(s):  
Chengwu An ◽  
Yongchang Fan ◽  
Dongsheng Lu ◽  
Zaiguang Li
Keyword(s):  
Thin Film ◽  
Superconducting Thin Film ◽  
High Tc

Direct Determination of the Velocity of Vortices in High-Tc Superconductors by a Non-Equilibrium Method

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3288-3291
Author(s):  
I. Kirschner ◽  
R. Laiho ◽  
A. C. Bódi ◽  
E. Lähderanta ◽  
I. Vajda
Keyword(s):  
Magnetic Field ◽  
Temperature Gradient ◽  
Vortex Motion ◽  
Direct Determination ◽  
Field Investigation ◽  
High Tc Superconductors ◽  
High Tc ◽  
Pinning Centers ◽  
Non Equilibrium

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.

MICROWAVE ABSORPTION STUDIES ON HIGH-Tc SUPERCONDUCTORS AND RELATED MATERIALS I—LOW-FIELD MICROWAVE ABSORPTION IN A BiSrCaCuO THIN FILM DEPOSITED BY MOCVD

1991 ◽  
Vol 05 (09) ◽  
pp. 667-674 ◽  
Author(s):  
K. SUGAWARA ◽  
T. SUGIMOTO ◽  
K. YASUIKE ◽  
D.J. BAAR ◽  
Y. SHIOHARA ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Microwave Absorption ◽  
Applied Field ◽  
Film Plane ◽  
Experimental Results ◽  
High Tc Superconductors ◽  
High Tc ◽  
Low Field ◽  
Absorption Studies

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.

HIGH Tc SUPERCONDUCTING THIN FILM DEPOSITION BY LASER INDUCED FORWARD TRANSFER

1992 ◽  
Vol 7 (1) ◽  
pp. 31-51 ◽  
Author(s):  
E. Fogarassy ◽  
C. Fuchs ◽  
S. de Unamuno ◽  
J. Perriere ◽  
F. Kerherve
Keyword(s):  
Thin Film ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Superconducting Thin Film ◽  
High Tc ◽  
Forward Transfer
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