scholarly journals Current noise in high Tc granular superconductors under non-stationary conditions of current and magnetic field

2003 ◽  
Author(s):  
Piero Mazzetti ◽  
Pierangelo Tura ◽  
Aldo Masoero ◽  
Aurelia Stepanescu
Keyword(s):  
Magnetic Field ◽  
Current Noise ◽  
High Tc ◽  
Granular Superconductors ◽  
Stationary Conditions

MAGNETIC FIELD AND CURRENT DEPENDENCE OF AVERAGE ACTIVATION ENERGY IN YBCO HIGH-Tc GRANULAR SUPERCONDUCTORS

2001 ◽  
Vol 15 (16) ◽  
pp. 555-559
Author(s):  
V. A. POPESCU ◽  
A. STEPANESCU
Keyword(s):  
Magnetic Field ◽  
Activation Energy ◽  
Temperature Dependence ◽  
Electrical Resistance ◽  
Electrical Current ◽  
High Tc ◽  
Current Dependence ◽  
Average Activation Energy ◽  
Granular Superconductors ◽  
Resistance Noise

The temperature dependence of the electrical resistance noise in the presence of a magnetic field in polycrystalline YBCO samples was fitted with an average activation energy which decreases with magnetic field and with bias electrical current.

Anisotropy of the electrical resistance in high-Tc granular superconductors under magnetic field

2000 ◽  
Vol 341-348 ◽  
pp. 1869-1870 ◽  
Author(s):  
D. Daghero ◽  
A. Masoero ◽  
P. Mazzetti ◽  
A. Stepanescu
Keyword(s):  
Magnetic Field ◽  
Electrical Resistance ◽  
High Tc ◽  
Granular Superconductors

Analysis And Interpretation Of Current Noise In High Tc Granular Superconductors During Their Resistive Transition

2007 ◽  
Author(s):  
V. Andreoli ◽  
C. Gandini ◽  
A. Masoero ◽  
P. Mazzetti ◽  
E. Monticone ◽  
...  
Keyword(s):  
Current Noise ◽  
Resistive Transition ◽  
High Tc ◽  
Granular Superconductors

Resistive noise of YBCO high-Tc granular superconductors in magnetic field

1995 ◽  
Vol 252 (3-4) ◽  
pp. 375-380 ◽  
Author(s):  
M. Celasco ◽  
G. Cone ◽  
V. Popescu ◽  
A. Masoero ◽  
A. Stepanescu
Keyword(s):  
Magnetic Field ◽  
High Tc ◽  
Granular Superconductors

THERMAL FLUCTUATION INFLUENCE ON THE RESISTIVE NOISE IN High-Tc GRANULAR SUPERCONDUCTORS

1999 ◽  
Vol 13 (22n23) ◽  
pp. 783-789
Author(s):  
V. POPESCU ◽  
M. CRISTEA ◽  
A. STEPANESCU
Keyword(s):  
Magnetic Field ◽  
Theoretical Model ◽  
Electrical Resistance ◽  
Thermal Noise ◽  
Thermal Fluctuation ◽  
Experimental Results ◽  
High Tc ◽  
Dc Magnetic Field ◽  
Granular Superconductors ◽  
Good Agreement

Using a recently developed percolative model, we have simulated the contribution of the thermal noise to the total electrical resistance fluctuation in YBCO granular superconductors under a dc magnetic field. The theoretical model is in good agreement with the experimental results.

MICROWAVE ABSORPTION STUDIES ON HIGH-Tc SUPERCONDUCTORS AND RELATED MATERIALS II: Electron Spin Resonance of DPPH Coated on Y1Ba2Cu3Oy as A Probe of Magnetic Field Variations

1991 ◽  
Vol 05 (11) ◽  
pp. 779-787
Author(s):  
K. SUGAWARA ◽  
D.J. BAAR ◽  
Y. SHIOHARA ◽  
S. TANAKA
Keyword(s):  
Magnetic Field ◽  
Temporal Variations ◽  
Zero Field ◽  
High Tc ◽  
Spin Resonance ◽  
Absorption Studies ◽  
Powder Particles ◽  
Increasing Temperature ◽  
Linewidth Broadening ◽  
Magnetic Field Variations

The ESR linewidth (∆H pp ) of DPPH coated on the surface of powder specimens of Y 1 Ba 2 Cu 3 O y has been studied under various magnetic field and temperature conditions. ∆H pp increases substantially with decreasing temperature in the field cooled case, whereas almost no linewidth broadening was found in the zero field cooled case. ∆H pp was found to be sensitive to the applied magnetic field. This effect was very pronounced at temperatures lower than 40 K, but decreased strongly with increasing temperature. The broadening of the resonance lineshape has been attributed to spatial and temporal variations of the fluxon distribution in the powder particles.

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.

Granular Aspects of High Tc Superconductivity

1990 ◽  
Vol 195 ◽  
Author(s):  
Guy Deutscher
Keyword(s):  
High Temperature ◽  
High Temperature Superconductivity ◽  
Original Publication ◽  
High Tc ◽  
High Tc Superconductivity ◽  
Bulk Ceramic ◽  
Ceramic Samples ◽  
Granular Superconductors

ABSTRACTAs Bednorz and Muller noted in their original publication reporting on the discovery of high temperature superconductivity, their oxides present many of the features of granular superconductors. This behavior was first primarily ascribed to poor connectivity of the grains in the bulk ceramic samples. but later studies have pointed out to more fundamental reasons for these similarities. We will discuss them after first reviewing the well established properties of low Tc granular superconductors.

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