Fabrication and characteristics of weak links between â- and ĉ-axis normal grains of Y1Ba2Cu3O7−x

1996 ◽  
Vol 11 (5) ◽  
pp. 1086-1093
Author(s):  
S. Mahajan ◽  
D. B. Buchholz ◽  
J. Lei ◽  
R. P. H. Chang ◽  
T. Hogan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Critical Current ◽  
Weak Coupling ◽  
Boundary Plane ◽  
Weak Links ◽  
Ion Milling ◽  
Flux Flow ◽  
Grain Boundary Plane ◽  
Current Voltage

We have used pulsed organometallic beam epitaxy (POMBE) to simultaneously deposit â- and ĉ-axis oriented Y1Ba2Cu3O7−x (YBCO) thin films at arbitrary locations on LaAlO3(100) substrates. Using photolithography and ion milling, several types of â-ĉ weak links have been fabricated at the boundary between the two films. The current-voltage (I-V) characteristics show a flux flow type behavior. The resistive transitions are broad and the critical current density is low, indicating weak coupling across these boundaries. With magnetic field applied parallel to the grain boundary plane, nonhysteretic I-V curves are obtained and the critical current goes to zero at an applied magnetic field of ∼7500 G.

BEHAVIOUR OF ORIENTED POLYCRYSTALLINE YBaCuO SUPERCONDUCTING THIN FILMS IN A WEAK MAGNETIC FIELD

1990 ◽  
Vol 04 (15) ◽  
pp. 975-982
Author(s):  
H.H. WEN ◽  
X.W. CAO ◽  
J.Z. SHI ◽  
W.Z. SHI ◽  
W.G. YAO ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Critical Field ◽  
Weak Magnetic Field ◽  
Flow Resistance ◽  
Weak Links ◽  
Superconducting Thin Films ◽  
Flux Flow ◽  
Granular Superconductivity ◽  
Oriented Polycrystalline

We determined a few characteristics of granular superconductivity through magnetoresistance measurements made on oriented polycrystalline YBaCuO superconducting thin films, and found that, at 77.3 K, the critical field for breaking a major portion of the superconducting weak links between grains was about 80 G, while the average lower critical field of the grains was about 175 G. Detail analyses on flux flow resistance show that a maximum of the increasing of flux flow resistance induced by a unit field will exist at a specified temperature, which we think is related to the dependence of the pinning energy on the temperature.

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.

scholarly journals Microwave properties of Fe(Se,Te) thin films in a magnetic field: pinning and flux flow

2020 ◽  
Vol 1559 ◽  
pp. 012055 ◽  
Author(s):  
Nicola Pompeo ◽  
Andrea Alimenti ◽  
Kostiantyn Torokhtii ◽  
Giulia Sylva ◽  
Valeria Braccini ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Microwave Properties ◽  
Flux Flow

Transport Measurements on Superconducting YBa2Cu3O7-δ Thin Film Lines

1989 ◽  
Vol 169 ◽  
Author(s):  
B. H. Moeckly ◽  
D. K. Lathrop ◽  
G. F. Redinbo ◽  
S. E. Russek ◽  
R. A. Buhrman
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Critical Current ◽  
Weak Link ◽  
High Sensitivity ◽  
Weak Links ◽  
Microwave Response ◽  
Field Response ◽  
Current Densities ◽  
Iv Curves

AbstractCritical current densities, magnetic field response, and microwave response have been measured for laser ablated YBa2Cu3O7-δ thin film lines on MgO and SrTiO3 substrates. Films on SrTiO3 have critical current densities > 1 x 106 A/cm2 at 77K and show uniform transport properties in lines of all sizes. Films on MgO have critical current densities which range between 102 and 106 A/cm2 at 77K and show considerable variation from device to device on the same chip. Narrow lines on MgO with low critical current densities show Josephson weak link structure which includes RSJ-like IV curves, microwave induced constant voltage steps, and a high sensitivity to magnetic field. The presence of the Josephson weak links is correlated with small amounts of misaligned grains in films on MgO.

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