SUPERCONDUCTIVITY ASSOCIATED WITH THE GRANULAR STRUCTURE IN Ba2YCu3O7−δ

1988 ◽  
Vol 02 (08) ◽  
pp. 1011-1015
Author(s):  
YONG ZHAO ◽  
QIRUI ZHANG ◽  
WEIYAN GUAN ◽  
JIANSHENG XIA ◽  
ZHENHUI HE ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Transport Properties ◽  
Single Phase ◽  
Granular Structure ◽  
Current Voltage ◽  
Granular Superconductivity ◽  
Current Voltage Characteristics ◽  
The Magnetic Field ◽  
Nonmonotonic Behavior

The dependence of the resistance on the magnetic field and the current-voltage characteristics of the single phase Ba 2 YCu 3 O 7−δ have been measured. The nonmonotonic behavior and a hysteresis of R(H) and the current-voltage characteristics suggest that the granular superconductivity exist in this material, and it plays an important role in transport properties.

JOSEPHSON JUNCTION NETWORK AS A TOOL TO SIMULATE INTERGRAIN SUPERCONDUCTING CHANNELS IN YBCO FILMS

2000 ◽  
Vol 14 (25n27) ◽  
pp. 3068-3073 ◽  
Author(s):  
G. ROTOLI ◽  
C. DE LEO ◽  
G. GHIGO ◽  
L. GOZZELINO ◽  
C. CAMERLINGO
Keyword(s):  
Magnetic Field ◽  
Josephson Junction ◽  
Transport Properties ◽  
Granular Structure ◽  
Current Dependence ◽  
Josephson Junction Network ◽  
Experimental Findings ◽  
Static Conditions ◽  
Vortex Phases ◽  
The Magnetic Field

Recent considerations on the physics of YBa 2 Cu 3 O 7-δ films made possible explaining their transport properties as flow of supercurrents through links between the granular structure of the film. The present work deals with the analysis of the Josephson junction network as a discrete set of parallel junctions (1D array) in quasi-static conditions and is aimed to compare the results of the simulations with the experimental findings, in particular with the plateau-like features in the critical current dependence on the magnetic field. Different regimes and vortex phases have been individuated and discussed.

Radiative and Electrical Properties of a Center-Post Cathode Magnetron Glow Discharge Device

1988 ◽  
Vol 42 (4) ◽  
pp. 576-583 ◽  
Author(s):  
Suzanne Tanguay ◽  
Richard Sacks
Keyword(s):  
Magnetic Field ◽  
Electrical Properties ◽  
Glow Discharge ◽  
Field Strength ◽  
Constant Current ◽  
Glow Discharge Plasma ◽  
Basic Operation ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
The Magnetic Field

Current-voltage characteristics and spatially resolved atomic emission data are used to describe the basic operation of a magnetron glow discharge plasma device. The low-pressure glow discharge lamp uses a center-post cathode and a concentric ring-shaped anode. A coaxial magnetic field of a few hundred Gauss is used to achieve magnetron operation where plasma electrons are trapped in closed paths which are concentric with the electrode structure. This results in dramatic changes in the radiative and electrical properties of the device. With constant current, lamp operating voltage may be reduced by more than a factor of two when the magnetic field is present. The effects of filler gas pressure and magnetic field strength on the current-voltage characteristics are presented. The presence of the magnetic field results in a radial contraction of the plasma. This contraction increases with increasing field strength and with decreasing pressure. Ion lines from the Ar filler gas are more affected by the field than are neutral-atom lines from the cathode material.

Point-contact spectroscopy probing the NbSe3 CDW gap in different crystallographic orientations

2002 ◽  
Vol 12 (9) ◽  
pp. 119-122
Author(s):  
A. A. Sinchenko ◽  
P. Monceau
Keyword(s):  
Magnetic Field ◽  
Low Temperature ◽  
Applied Magnetic Field ◽  
Energy Gap ◽  
Point Contact ◽  
Point Contacts ◽  
Energy Gaps ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Crystallographic Orientations

We have measured the differential current-voltage characteristics of normal metal-NbSe3 direct point contacts (without insulating barrier) formed along different crystallographic orientations under applied magnetic field with different orientations. At low temperature two energy gaps, $\Delta_{p1}$ and $\Delta_{p2}$, corresponding to the high and the low-temperature CDW were observed simultaneously as a singulanty of the excess resistance which is attributed to an analog of Andreev reflection, in which the incident electron reflects on the Peierls energy gap barriers with its charge unchanged. An applied magnetic field up to 8.5 T does not lead to a change in the density of states and in the Peierls energy gaps, suggesting that the large magnetoresistance observed in NbSe3 might not result from the change in the CDW order parameter with magnetic field but rather from the increase of scattering of non-condensed to CDW carriers.

scholarly journals Nonlinear Response of a Superconductor of the Bi-Sr-Ca-Cu-O System to an Alternating Magnetic Field in the Superconducting Transition Temperature Range

2018 ◽  
Vol 185 ◽  
pp. 08005
Author(s):  
Alexander Sergeev ◽  
Igor Golev ◽  
Victoria Gvozdevskaya ◽  
Anastasia Barkalova
Keyword(s):  
Magnetic Field ◽  
Nonlinear Response ◽  
Alternating Magnetic Field ◽  
Resistive State ◽  
Superconducting Transition ◽  
Critical Temperatures ◽  
Temperature Range ◽  
Nonlinear Properties ◽  
Current Voltage ◽  
Current Voltage Characteristics

The nonlinear response of the superconductor of the Bi-Sr-Ca-Cu-O system in the temperature range of the superconducting transition under the action of a harmonic alternating magnetic field is experimentally studied. For multiphase superconductors having in their volume regions with distinct critical temperatures, the effect of odd harmonics in the response signal is observed. The contribution of crystallites and the system of weak bonds between the crystallites in the nonlinear response is singled out. It was found that the nonlinear properties of the investigated samples in the resistive state are determined mainly by the nonlinear current-voltage characteristics of the system of weak bonds between the crystallites.

scholarly journals Effect of confinement potential shape on the electronic, thermodynamic, magnetic and transport properties of a GaAs quantum dot at finite temperature

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
K. Luhluh Jahan ◽  
Bahadir Boyacioglu ◽  
Ashok Chatterjee
Keyword(s):  
Magnetic Field ◽  
Heat Capacity ◽  
Quantum Dot ◽  
Transport Properties ◽  
Average Energy ◽  
Persistent Current ◽  
Confinement Potential ◽  
Potential Shape ◽  
Gaas Quantum Dot ◽  
The Magnetic Field

Abstract The effect of the shape of the confinement potential on the electronic, thermodynamic, magnetic and transport properties of a GaAs quantum dot is studied using the power-exponential potential model with steepness parameter p. The average energy, heat capacity, magnetic susceptibility and persistent current are calculated using the canonical ensemble approach at low temperature. It is shown that for soft confinement, the average energy depends strongly on p while it is almost independent of p for hard confinement. The heat capacity is found to be independent of the shape and depth of the confinement potential at low temperatures and for the magnetic field considered. It is shown that the system undergoes a paramagnetic-diamagnetic transition at a critical value of the magnetic field. It is furthermore shown that for low values of the potential depth, the system is always diamagnetic irrespective of the shape of the potential if the magnetic field exceeds a certain value. For a range of the magnetic field, there exists a window of p values in which a re-entrant behavior into the diamagnetic phase can occur. Finally, it is shown that the persistent current in the present quantum dot is diamagnetic in nature and its magnitude increases with the depth of the dot potential but is independent of p for the parameters considered.

Sign in / Sign up

Export Citation Format

Share Document