scholarly journals NON-EQUILIBRIUM RADIATION RESPONSE AND DECOUPLING OF VORTEX-ANTIVORTES PAIRS IN TWO-DIMENSIONAL HIGH-Tc SUPERCONDUCTORS

2000 ◽  
Vol 49 (5) ◽  
pp. 989
Author(s):  
XU KE-XI
Keyword(s):  
Radiation Response ◽  
Two Dimensional ◽  
High Tc Superconductors ◽  
High Tc ◽  
Equilibrium Radiation ◽  
Non Equilibrium

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.

TWO-DIMENSIONAL ANTIFERROMAGNETIC ORDERING IN HIGH-Tc SUPERCONDUCTORS WITH LOW OXYGEN CONTENT

1989 ◽  
Vol 03 (05) ◽  
pp. 711-717 ◽  
Author(s):  
YU. T. PAVLUKHIN ◽  
N. G. HAINOVSKY ◽  
YA. YA. MEDIKOV ◽  
A. I. RYKOV
Keyword(s):  
Oxygen Content ◽  
Two Dimensional ◽  
Low Oxygen ◽  
High Tc Superconductors ◽  
High Tc ◽  
Antiferromagnetic Ordering

Annealing of tweed microstructure in high Tc superconductors in the presence of impurities

1995 ◽  
Vol 10 (8) ◽  
pp. 1864-1871 ◽  
Author(s):  
K. Parlinski ◽  
Y. Watanabe ◽  
K. Ohno ◽  
Y. Kawazoe
Keyword(s):  
Low Temperature ◽  
Domain Walls ◽  
Nearest Neighbor ◽  
Oxygen Deficit ◽  
Two Dimensional ◽  
Dimensional Model ◽  
High Tc Superconductors ◽  
High Tc ◽  
Large Coupling ◽  
Linear Chains

A two-dimensional model of oxygen-deficit layer of superconducting material YBa2Cu3O7 has been simulated by the molecular-dynamics technique in order to study the influence of the impurities in the site of copper on the low-temperature microstructure. The microstructure pattern arises as a result of quenching the system from a high-temperature tetragonal phase to the low-temperature orthorhombic one and subsequent annealing. The potential of the impurity is modified in such a way that it promotes occupation of opposite nearest-neighbor sites around impurity by an oxygen and vacancy simultaneously. The simulations of the annealing processes showed that the domain pattern becomes very tiny with increased concentration of randomly distributed impurities. Domains of larger sizes would appear if the impurities were able to diffuse to the domain walls. This is confirmed by annealing the sample containing linear chains of impurities. The tweed microstructure depends on the magnitude of the force constants of the elastic subsystem, and at too large coupling the randomly distributed impurities are not able to pin the stiff domain walls. The results resemble the electron-microscope photographs made for cobalt in YBa2(Cu1−xCox)3O7−δ.

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