ac susceptibility and weak-link-free behavior in an epitaxial film ofGdBa2Cu3O7−δ

1992 ◽  
Vol 46 (14) ◽  
pp. 9190-9194 ◽  
Author(s):  
J. W. Li ◽  
R. L. Wang ◽  
H. R. Yi ◽  
H. C. Li ◽  
B. Yin ◽  
...  
Keyword(s):  
Epitaxial Film ◽  
Weak Link ◽  
Ac Susceptibility ◽  
Free Behavior

Weak-Link Nature of AC Susceptibility in the Grain-Oriented YBa2Cu3O7−δ Superconducting Ceramics

1991 ◽  
Vol 123 (1) ◽  
pp. 275-283 ◽  
Author(s):  
S. S. Kim ◽  
T. T. Srinivasan ◽  
R. E. Newnham
Keyword(s):  
Weak Link ◽  
Ac Susceptibility ◽  
Superconducting Ceramics

EVIDENCES OF JOSEPHSON WEAK LINK NETWORK IN SINTERED BULK Y1Ba2Cu3O7−x OXIDE

1988 ◽  
Vol 02 (03n04) ◽  
pp. 427-433 ◽  
Author(s):  
YONGJIA QIAN ◽  
JINGWU QIU ◽  
KAIYUAN CHEN ◽  
BING ZHOU ◽  
BAICAI MIAO ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Critical Current ◽  
Weak Link ◽  
Ac Susceptibility ◽  
Point Contact ◽  
Transport Current ◽  
Oxide Superconductor ◽  
Current Zero ◽  
Zero Voltage

Measurements of point-contact tunneling, AC susceptibility vs transport current, zero voltage supercurrent under microwave irradiation and critical current as a function of temperature have been carried out on high Tc oxide superconductor Y 1 Ba 2 Cu 3 O 7−x. The results of these measurements can be interpreted by the assumption of existence of Josephson weak link network in the oxide.

TEMPERATURE AND FIELD VARIATION OF AC SUSCEPTIBILITY ON Mn DOPED YBa2Cu3O7-δ SUPERCONDUCTOR

2003 ◽  
Vol 17 (03) ◽  
pp. 383-392 ◽  
Author(s):  
E. ISAAC SAMUEL ◽  
V. SESHU BAI
Keyword(s):  
Critical Current Density ◽  
Temperature Variation ◽  
Critical Current ◽  
Imaginary Part ◽  
Current Density ◽  
Weak Link ◽  
Ac Susceptibility ◽  
Ac Loss ◽  
Field Variation ◽  
Mn Doped

Temperature variation of AC susceptibility has been measured on YBa 2( Cu 1 - x- Mn x)3 O 7-δ samples with x values 0, 0.01, 0.015, 0.02, 0.025, 0.035 and 0.05, YBa 2( Cu 0.075 Fe 0.025)3 O 7-δ and YBa 2( Cu 0.075 Ni 0.025)3 O 7-δ samples in the temperature range from 10 to 120 K. The weak link (inter-granular) and granular responses are distinctly pronounced at the studied fields of 0.2 to 30 Oe. The temperature variation of weak link critical current density Jcw(T) indicates the inter-granular coupling to be of superconductor-insulator-superconductor (SIS) type. The weak link AC loss calculated from the imaginary part of the AC susceptibility χ′′(T) is found to exhibit a power relation with temperature, with an average exponent value of 1.96. Field variation of AC susceptibility measured at 50 K and 77 K were well modelled with Kim's relation and the Jcw at 50 K and 77 K were estimated from the fit parameters.

scholarly journals Superconducting Properties and Electron Scattering Mechanisms in a Nb Film with a Single Weak-Link Excavated by Focused Ion Beam

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7274
Author(s):  
Marlon Ivan Valerio-Cuadros ◽  
Davi Araujo Dalbuquerque Chaves ◽  
Fabiano Colauto ◽  
Ana Augusta Mendonça de Oliveira ◽  
Antônio Marcos Helgueira de Andrade ◽  
...  
Keyword(s):  
Electron Scattering ◽  
Focused Ion Beam ◽  
Weak Link ◽  
Ion Beam ◽  
Ac Susceptibility ◽  
Granular System ◽  
Additional Contribution ◽  
Scattering Mechanisms ◽  
Important Research Topic ◽  
Theory Framework

Granularity is one of the main features restricting the maximum current which a superconductor can carry without losses, persisting as an important research topic when applications are concerned. To directly observe its effects on a typical thin superconducting specimen, we have modeled the simplest possible granular system by fabricating a single artificial weak-link in the center of a high-quality Nb film using the focused ion beam technique. Then, its microstructural, magnetic, and electric properties in both normal and superconducting states were studied. AC susceptibility, DC magnetization, and magneto-transport measurements reveal well-known granularity signatures and how they negatively affect superconductivity. Moreover, we also investigate the normal state electron scattering mechanisms in the Boltzmann theory framework. The results clearly demonstrate the effect of the milling technique, giving rise to an additional quadratic-in-temperature contribution to the usual cubic-in-temperature sd band scattering for the Nb film. Finally, by analyzing samples with varying density of incorporated defects, the emergence of the additional contribution is correlated to a decrease in their critical temperature, in agreement with recent theoretical results.

Hysteretic Dependence of Critical Current on Applied Magnetic Field and Magnetic Irreversmujty Line Crossings in Polycrystalline YBa2Cu3C7

1989 ◽  
Vol 169 ◽  
Author(s):  
Thomas R. Askew ◽  
Richard B. Flippen
Keyword(s):  
Magnetic Field ◽  
Critical Current ◽  
Weak Link ◽  
Ac Susceptibility ◽  
Transport Critical Current Density ◽  
High Quality ◽  
Conduction Model ◽  
Trapped Flux ◽  
Magnetic Irreversibility ◽  
Critical Current Density Jc

AbstractThe transport critical current density Jc has been measured in high quality poly-crystalline YBa2Cu3C7 as a function of temperature and for various sweeps of sub-Tesla applied magnetic fields. Large increases over the virgin response were observed in Jc at fields of a few hundred gauss and are attributed to trapped flux in the samples. The amount of trapped flux was measured and correlated to the change at Jc at various temperatures. The position of the magnetic irreversibility line was measured by field induced absorption shift in AC susceptibility. The various data are discussed in the context of the weak link conduction model.

Ac susceptibility weak link characterization in the Bi-Pb-Ca-Sr-Cu-O thick films on (in) Ag tape

1993 ◽  
Vol 1 (7-9) ◽  
pp. 1007-1013 ◽  
Author(s):  
P.E. Kazin ◽  
T.E. Os'kina ◽  
Yu.D. Tretyakov
Keyword(s):  
Weak Link ◽  
Ac Susceptibility ◽  
Thick Films

Structural analysis of a Σ5 grain boundary in YBa2Cu3O7δ

1993 ◽  
Vol 51 ◽  
pp. 942-943
Author(s):  
J.-Y. Wang ◽  
Y. Zhu ◽  
A.H. King ◽  
M. Suenaga
Keyword(s):  
Grain Boundary ◽  
Lattice Mismatch ◽  
Weak Link ◽  
Coincidence Site Lattice ◽  
Large Angle ◽  
Dislocation Core ◽  
Superconducting Order Parameter ◽  
Outstanding Problem ◽  
Transmission Electron

One outstanding problem in YBa2Cu3O7−δ superconductors is the weak link behavior of grain boundaries, especially boundaries with a large-angle misorientation. Increasing evidence shows that lattice mismatch at the boundaries contributes to variations in oxygen and cation concentrations at the boundaries, while the strain field surrounding a dislocation core at the boundary suppresses the superconducting order parameter. Thus, understanding the structure of the grain boundary and the grain boundary dislocations (which describe the topology of the boundary) is essential in elucidating the superconducting characteristics of boundaries. Here, we discuss our study of the structure of a Σ5 grain boundary by transmission electron microscopy. The characterization of the structure of the boundary was based on the coincidence site lattice (CSL) model.Fig.l shows two-beam images of the grain boundary near the projection. An array of grain boundary dislocations, with spacings of about 30nm, is clearly visible in Fig. 1(a), but invisible in Fig. 1(b).

Effect of thermal annealing on grain boundary chemistry of polycrystalline TiBa2Ca2Cu3Oy films

1994 ◽  
Vol 52 ◽  
pp. 968-969
Author(s):  
Z. L. Wang ◽  
C. L. Briant ◽  
J. DeLuca ◽  
A. Goyal ◽  
D. M. Kroeger ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Weak Link ◽  
Zero Field ◽  
Stabilized Zirconia ◽  
Local Texture ◽  
Transmission Electron ◽  
Axis Alignment ◽  
Boundary Chemistry ◽  
Small Misorientation ◽  
Misorientation Angles

Recent studies have shown that spray-pyrolyzed films of the Tl-1223 compound (TlxBa2Ca2Cu3Oy, with 0.7 < × < 0.95) on polycrystalline yttrium stabilized zirconia substrates can be prepared which have critical current density Jc near 105 A/cm2 at 77 K, in zero field. The films are polycrystalline, have excellent c-axis alignment, and show little evidence of weak-link behavior. Transmission electron microscopy (TEM) studies have shown that most grain boundaries have small misorientation angles. It has been found that the films have a nigh degree of local texture indicative of colonies of similarly oriented grains. It is believed that inter-colony conduction is enhanced by a percolative network of small angle boundaries at colony interfaces. It has also been found that Jc is increased by a factor of 4 - 5 after the films were annealed at 600 °C in oxygen. This study is thus carried out to determine the effect on grain boundary chemistry of the heat treatment.

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