Estimation of Local Current Transport Properties in Thin Film Superconductor Based on Scanning Hall-probe Microscopy

2012 ◽  
Vol 1434 ◽  
Author(s):  
Kohei Higashikawa ◽  
Kei Shiohara ◽  
Masayoshi Inoue ◽  
Takanobu Kiss ◽  
Masateru Yoshizumi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Critical Current Density ◽  
Electric Field ◽  
Critical Current ◽  
Current Density ◽  
Limiting Factors ◽  
Hall Probe ◽  
Scanning Hall Probe Microscopy ◽  
Field Criterion

ABSTRACTTo enhance a global critical current in a superconductor, it is indispensable to understand current limiting factors and their influence on such a critical current. From this point of view, we have investigated in-plane distribution of local critical current density and its electric field criterion in a thin-film superconductor by using scanning-Hall probe microscopy. In a remanent state, after the application of sufficiently high magnetic field to a sample, current flows at critical current density according to the critical state model. Such distribution of current density was estimated from that of measured magnetic field using the Biot-Savart law. Furthermore, the corresponding electric field criterion was evaluated from the relaxation of such remanent magnetic field by considering Faraday’s law. This means that we could estimate in-plane distribution of local critical current density as a function of electric field criterion in a nondestructive manner. This characterization method would be very helpful for finding current limiting factors in a thin-film superconductor and their influence on its global current density versus electric field properties which would usually be obtained by four-probe method.

Angular Dependence of Magnetic Field on Critical Current Density in Tl2Ba2Ca2Cu3Ox Thin Film

1991 ◽  
pp. 555-558
Author(s):  
Toshihide Nabatame ◽  
Yukio Saito ◽  
Katsuzo Aihara ◽  
Tomoichi Kamo ◽  
Shin-Pei Matsuda
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Critical Current Density ◽  
Critical Current ◽  
Angular Dependence ◽  
Current Density

scholarly journals Real Critical Current Density and Material Power Law of YBa2Cu3O7-d Epitaxial Thin Film

2000 ◽  
Vol 53 (6) ◽  
pp. 821
Author(s):  
Lei Shan ◽  
Sahr Augustine Aruna ◽  
Xiao-Nong Xu ◽  
Zhi-He Wang ◽  
Xin Jin
Keyword(s):  
Thin Film ◽  
Critical Current Density ◽  
Critical Current ◽  
Power Law ◽  
Current Density ◽  
Epitaxial Thin Film ◽  
Pinning Potential ◽  
Material Power ◽  
Electronic Field ◽  
Field Criterion

The current–voltage characteristics have been measured on aYBa2Cu3O7-δ epitaxial thin film. Using a material power law, we determine the temperature and field dependencies of the characteristic pinning potential UJand the real critical current density Jc at different fields and temperatures. It is shown that Jc is completely different from the conventional critical current density JE, which is determined by the electronic-field criterion. Thus, the time-honoured electronic-field criterion is no longer reasonable for high-Tc superconductors. By further investigation of the results of Jc and UJ, we are able to present a physical picture of the transformation of the pinning potential well with increasing temperature and hence determine the transition point from vortex-glass phase to vortex-liquid phase.

scholarly journals Enhancing the effective critical current density in a Nb superconducting thin film by cooling in an inhomogeneous magnetic field

2021 ◽  
Vol 119 (2) ◽  
pp. 022602
Author(s):  
D. A. D. Chaves ◽  
I. M. de Araújo ◽  
D. Carmo ◽  
F. Colauto ◽  
A. A. M. de Oliveira ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Inhomogeneous Magnetic Field ◽  
Superconducting Thin Film

Some Observations on the Measurement of Transport Critical Current Density in Bulk Ceramic Superconductive Wire

1992 ◽  
Vol 275 ◽  
Author(s):  
S. Samajdar ◽  
Shyam K. Samanta
Keyword(s):  
Critical Current Density ◽  
Electric Field ◽  
Critical Current ◽  
Current Density ◽  
Constant Electric Field ◽  
Transport Critical Current Density ◽  
Theoretical Treatment ◽  
Ceramic Phase ◽  
Current Voltage ◽  
Field Criterion

ABSTRACTThe transition temperature and the critical current density of a bulk YBa2Cu3O7−x-Ag microcomposite superconductive wire, prepared by powder processing followed by warm extrusion, have been measured employing the standard AC four probe technique. Measurements were performed, at 15K and zero applied field, with varying distance between the voltage contacts, while the current contacts remained a constant distance apart. It is observed that the resistance-temperature behavior remained identical in all the cases. Interestingly, the critical current density, determined from the experimentally recorded current-voltage characteristic by applying a constant electric field criterion, is seen to increase significantly, smoothly and steadily with increasing voltage tap length. However, the critical current density remains virtually unchanged if a constant voltages criterion is applied for its determination. This paradoxical dependence of critical current density, a material property, on measurement length has been explained with the help of a simple theoretical treatment, taking into account the nature of current-voltage chracteristics as well as the phenomenon of current transfer through the metallic to the superconducting ceramic phase. It is suggested that the constant electric field criterion may not be an appropriate one to use in the evaluation of critical current density of metal-ceramic superconductive composites.

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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