THREE-DIMENSIONAL TlBaCaCuO THICK FILM DC SQUID

1993 ◽  
Vol 07 (09) ◽  
pp. 633-639
Author(s):  
YUHUA HUO ◽  
SHOUZHEN ZHAO ◽  
FANGWU SHAO ◽  
CHANGCHUN WEI ◽  
LINGWEN ZENG ◽  
...  
Keyword(s):  
Thin Film ◽  
Critical Current Density ◽  
Thick Film ◽  
Critical Current ◽  
Current Density ◽  
Screen Printing ◽  
Three Dimensional ◽  
Bias Current ◽  
Zero Resistance ◽  
Dc Bias

TlBaCaCuO thick films were fabricated by the method of screen printing. Zero resistance temperature of 110 K–118 K and critical current density of about 102 A/cm 2 at 77 K were obtained. The thickness of the film was about 30 μm. Using the thick film we have fabricated three-dimensional DC SQUID. The flux modulated V–I curve, V–H curve, and triangular patterns in response to flux applied at the different dc bias current were measured. The results showed that not only TlBaCaCuO thick film DC SQUID was like that from TlBaCaCuO thin film in good microwave behaviour but also the processes of fabricating thick film DC SQUID were easy.

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.

Characterization of Epitaxial Superconducting YBacuO Thin Films with Three Different Orientations

1989 ◽  
Vol 169 ◽  
Author(s):  
X.K. Wang ◽  
D.X. Li ◽  
S.N. Song ◽  
J.Q. Zheng ◽  
R.P.H. Chang ◽  
...  
Keyword(s):  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Orientation Dependence ◽  
Zero Field ◽  
Epitaxial Thin Films ◽  
Oriented Film ◽  
Zero Resistance ◽  
Xrd Patterns

AbstractEpitaxial thin films of YBaCuO were prepared by multilayer deposition from Y, Cu, and BaF2 sources with: (1) the a‐axis perpendicular to (100)SrTiO3; (2) the c‐axis perpendicular to (100)SrTiO3; and (3) the [110] axis perpendicular to (110)SrTiO3. XRD patterns as well as SEM and HREM images confirm that the films are highly oriented, essentially epitaxial. Both the a‐axis oriented and the c‐axis oriented films exhibit zero resistance at 91K. The [110] oriented film shows the sharpest transiton with a transition width of IK and zero resistance at 85K. The zero field critical current density, Jc, determined magnetically, is in excess of 107A/cm2 at 4.4K and 1.04 x 106A/cm2 at 77K for the c‐axis oriented film; for the a‐axis oriented film we obtained 6.7 x 106A/cm2 at 4.4K and 1.2 x 105A/cm2 at 77K. The orientation dependence of the critical current density in the basal plane of the a‐axis oriented film was studied. The largest Jc's occur along the in‐plane <100> axes of the substrate.

Grain Boundaries and Critical Current Density of YBa2Cu3O7-y Thick Film Prepared by Liquid Phase Epitaxy

1996 ◽  
pp. 775-778
Author(s):  
Tasuku Kitamura ◽  
Jian-Guo Wen ◽  
Yuh Shiohara ◽  
Naoki Koshizuka ◽  
Izumi Hlrabayashi ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Critical Current Density ◽  
Grain Boundaries ◽  
Thick Film ◽  
Critical Current ◽  
Current Density ◽  
Liquid Phase Epitaxy

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.

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