The behaviour of the intergranular critical current density of polycrystalline, c-axis oriented YBa2Cu3O7−δ films

1996 ◽  
Vol 46 (S3) ◽  
pp. 1287-1288
Author(s):  
Wolfgang Widder ◽  
Ludwig Bauernfeind ◽  
Hans F. Braun ◽  
Hubert Burkhardt
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Intergranular Critical Current Density

INTERGRANULAR PROPERTIES OF (Y1-x-yZrxCay)Ba2Cu3O7-δ COMPOUNDS

1999 ◽  
Vol 13 (13) ◽  
pp. 1645-1654 ◽  
Author(s):  
I. GR. DEAC ◽  
E. BURZO ◽  
A. V. POP ◽  
V. POP ◽  
R. TETEAN ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Ac Susceptibility ◽  
Temperature Dependent ◽  
Susceptibility Data ◽  
Dc Magnetic Field ◽  
Complex Susceptibility ◽  
Granular Superconductors ◽  
Intergranular Critical Current Density

The intergranular properties of ( Y 1-x-y Zr x Ca y) Ba 2 Cu 3 O 7-δ ceramics were studies by using temperature-dependent ac susceptibility measurements at zero dc magnetic field. The intergranular critical current density was determined from ac susceptibility data by varying the field amplitude H ac . From the imaginary part of the complex susceptibility, χ″(T), we have determined the temperature dependence of the critical current density by using the Bean's model. The ac field dependencies of the intergrain χ″-peak temperatures T p are linear and agree with Müller critical state model. The results were analyzed in terms of superconductor-insulator-superconductor (SIS)-and superconductor-normal-superconductor (SNS)-type models for granular superconductors.

AC SUSCEPTIBILITY OF YBCO SUPERCONDUCTING THIN FILMS

2006 ◽  
Vol 20 (15) ◽  
pp. 923-929
Author(s):  
C. SBÂRCIOG ◽  
T. R. REDAC ◽  
I. GR. DEAC
Keyword(s):  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Ac Susceptibility ◽  
Superconducting Thin Films ◽  
Superconducting Transition ◽  
Susceptibility Data ◽  
Complex Susceptibility ◽  
Intergranular Critical Current Density

Ca -doped (x = 0.00, 0.07 and 0.20) epitaxial Y 1-x Ca x Ba 2 Cu 3 O 7-δ thin films were prepared on SrTiO 3 (100) by PLD technique. The superconducting transition temperature is found to decrease with increasing Ca content. The AC-susceptibility data were used to determine the intergranular critical current density, when varying the field amplitude H AC . The temperature dependence of critical current density was determined from the imaginary part of the complex susceptibility, χ′′(T), using Xing's relation. The results were analyzed in terms of superconductor-insulator-superconductor (SIS) and superconductor-normal-superconductor (SNS) type models.

The Influence of Heat Treatment on Electric Properties of Bulk (Bi,Pb):2223 Superconductor

2003 ◽  
Vol 17 (21) ◽  
pp. 3807-3811
Author(s):  
V. Pop
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Electrical Resistance ◽  
Sintering Temperature ◽  
Electrical Measurement ◽  
Field Amplitude ◽  
Transition Width ◽  
Ac Field ◽  
Intergranular Critical Current Density

The (Bi,Pb)(Sr,Ba) :2223 samples were prepared using different sintering temperatures. The electrical properties were investigated by electrical resistance and V–I characteristics measurements. The increase of sintering temperature induces the decrease of transition width and the increase of intergranular critical current density Jcj and phase purity. The critical current density from electrical measurement agrees with the results obtained from complex magnetic susceptibility measurements function of temperature and AC field amplitude.

ANOMALOUS INCREASE OF THE TRANSPORT AND INDUCTIVE CRITICAL CURRENT DENSITY DUE TO LOW DC-FIELD COOLING IN SINTERED RBa2Cu3O7−x HIGH Tc SUPERCONDUCTORS

1991 ◽  
Vol 05 (26) ◽  
pp. 1727-1733
Author(s):  
T. PUIG ◽  
M. PONT ◽  
J.S. MUÑOZ
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Ac Susceptibility ◽  
Transport Critical Current Density ◽  
Zero Field ◽  
High Tc ◽  
Current Densities ◽  
Magnetic Flux Pinning ◽  
Intergranular Critical Current Density

The transport critical current density of bulk sintered samples of RBa2Cu3O7−x with R=Y, Gd, Ho, and Er has been determined at 77 K from I–V curves at different applied dc-magnetic fields (0≤H≤20 Oe), also the ac-susceptibility as a function of ac-field amplitude has been measured with a superimposed dc-magnetic field from 0 to 30 Oe at 77 K. The transport and magnetic (inductive) critical current densities, are clearly larger in field cooled samples than in zero field cooled samples. Likewise, the degree of shielding as determined from the ac-susceptibility measurements is larger for field cooled samples than for zero field cooled. This anomalous behaviour can be explained in terms of the magnetic flux pinning present in the grains when the sample is field cooled, which leads to a decrease in the magnetic induction of the intergrain region and therefore to a higher intergranular critical current density compared to a zero field cooled sample.

Microstructural characterization of YBa2Cu3O7-x thin films formed by metalorganic CVD

1991 ◽  
Vol 49 ◽  
pp. 1080-1081
Author(s):  
P. Lu ◽  
W. Huang ◽  
C.S. Chern ◽  
Y.Q. Li ◽  
J. Zhao ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Film Growth ◽  
Chemical Vapor ◽  
Microstructural Characterization ◽  
Ion Milling ◽  
Conventional Grinding

The YBa2Cu3O7-x thin films formed by metalorganic chemical vapor deposition(MOCVD) have been reported to have excellent superconducting properties including a sharp zero resistance transition temperature (Tc) of 89 K and a high critical current density of 2.3x106 A/cm2 or higher. The origin of the high critical current in the thin film compared to bulk materials is attributed to its structural properties such as orientation, grain boundaries and defects on the scale of the coherent length. In this report, we present microstructural aspects of the thin films deposited on the (100) LaAlO3 substrate, which process the highest critical current density.Details of the thin film growth process have been reported elsewhere. The thin films were examined in both planar and cross-section view by electron microscopy. TEM sample preparation was carried out using conventional grinding, dimpling and ion milling techniques. Special care was taken to avoid exposure of the thin films to water during the preparation processes.

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