Evidence for Weak Link Effects in Epitaxial Thin Films of YBCO on LaAlO3

1992 ◽  
Vol 275 ◽  
Author(s):  
J. Bohandy ◽  
B. F. Kim ◽  
K. Moorjani ◽  
F. J. Adrian
Keyword(s):  
Thin Films ◽  
Grain Boundaries ◽  
Weak Link ◽  
Weak Links ◽  
Superconducting Thin Films ◽  
Epitaxial Thin Films ◽  
High Quality ◽  
Microwave Loss

ABSTRACTEvidence of weak link effects in epitaxial thin films of YBa2Cu3O7-yon LaAlO3 is obtained from magnetically modulated resistance (MMR) measurements. This result suggests that weak links could provide a mechanism for the residual microwave loss in high quality superconducting thin films which contain predominantly low angle grain boundaries.

YBa2Cu3O7−x Grain Boundary Weak Links on MgO Bicrystal

1992 ◽  
Vol 275 ◽  
Author(s):  
H. B. Lu ◽  
S. L. Tu ◽  
J. J. Wang ◽  
J. Lin ◽  
T. W. Huang ◽  
...  
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Weak Link ◽  
Weak Links ◽  
Artificial Boundaries ◽  
Tilt Boundaries ◽  
Preliminary Study ◽  
High Degree

ABSTRACTThe characteristics of YBa2Cu3O7−x (YBCO) thin films by laser ablation on MgO bicrystals have been investigated. The bicrystals were fabricated by hot pressing two single crystals with the configuration of [001] tilt boundaries. The YBCO films were epitaxial grown with C-axis normal to the both adjacent grains of bicrystals. The FWHM about (005) reflection was 0.4–0.5 degree, indicating the high degree of the oriention for the film with small mosaic spread. Our preliminary study showed that the typical value of Jc on either side of the bicrystal boundary was 0.4–10×106 A/cm2 at 15K, while that across the 10° tilt boundaries was 0.3–9×105 A/cm2 at 15K. These results implied that the artificial grain boundaries effectively weakened the supercurrent, and therefore, the weak-link properties of artificial boundaries were more easily controllable than those of naturally occuring grain boundaries.

MAGNETIC RESISTIVITY IN Bi2Sr2Ca(Cu1-xCox)2Od EPITAXIAL THIN FILMS

2007 ◽  
Vol 21 (01) ◽  
pp. 127-132
Author(s):  
T. R. YANG ◽  
G. ILONCA ◽  
V. TOMA ◽  
P. BALINT ◽  
M. BODEA
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Activation Energy ◽  
Glass Transition ◽  
Effective Activation Energy ◽  
Epitaxial Thin Films ◽  
Effective Activation ◽  
High Quality ◽  
Plastic Deformations ◽  
Magnetic Resistivity

The scaling behavior of the effective activation energy of high-quality epitaxial c-oriented Bi 2 Sr 2 Ca ( Cu 1-x Co x)2 O d thin films with 0≤x ≤0.025 has been studied as a function of temperature and magnetic field. For all samples, the effective activation energy scales as U(T, μoH)=Uo(1-T/T c )mHn with exponent m=1.25±0.03, n=-1/2 and the field scaling 1/μoH and -UμoH for thick films and ultra thin films, respectively. The results are discussed taking into account of the influence of the Co substitution with a model in which U(T, H) arises from plastic deformations of the viscous flux liquid above the vortex-glass transition temperature.

HIGH-QUALITY Tl2Ba2Ca2Cu3O10 THIN FILMS FABRICATED VIA LASER ABLATION

1993 ◽  
Vol 07 (01) ◽  
pp. 19-23 ◽  
Author(s):  
W. A. LUO ◽  
Y. Q. TANG ◽  
Y. Z. CHEN ◽  
I. N. CHAN ◽  
K. Y. CHEN ◽  
...  
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Critical Current Density ◽  
Current Density ◽  
Superconducting Thin Films ◽  
X Ray Diffraction ◽  
High Quality ◽  
Step Process ◽  
X Ray ◽  
Zero Resistance

In this letter, we describe results obtained via laser ablation to fabricate Tl 2 Ba 2 Ca 2 Cu 3- O 10 superconducting thin films using a two-step process. We found that the zero-resistance temperatures are up to 121 K, while the onset temperatures are up to 125 K. The T c and J c are mainly determined by a non-contact new technique for high-T c films. The typical critical current density, J c , is about 106 A/cm 2 at 77 K. X-ray diffraction showed that the superconducting thin films are nearly single 2223 phase and are highly oriented.

High-quality superconducting thin films of Bi2Sr2Ca2Cu3Ox grown in situ by metalorganic CVD

Nature ◽  
1992 ◽  
Vol 355 (6358) ◽  
pp. 327-328 ◽  
Author(s):  
K. Endo ◽  
H. Yamasaki ◽  
S. Misawa ◽  
S. Yoshida ◽  
K. Kajimura
Keyword(s):  
Thin Films ◽  
Superconducting Thin Films ◽  
High Quality

scholarly journals Stability of Tl–Ba–Ca–Cu–O superconducting thin films

1999 ◽  
Vol 14 (12) ◽  
pp. 4482-4488 ◽  
Author(s):  
M. P. Siegal ◽  
D. L. Overmyer ◽  
E. L. Venturini ◽  
R. R. Padilla ◽  
P. N. Provencio
Keyword(s):  
Thin Films ◽  
Thermal Cycling ◽  
High Temperatures ◽  
Superconducting Thin Films ◽  
Epitaxial Thin Films ◽  
Cryogenic Temperatures ◽  
The Stability

We report the stability of TlBa2CaCu2O7 and Tl2Ba2CaCu2O8 on LaAlO3(100) epitaxial thin films, under a variety of conditions. All films are stable in acetone and methanol and with repeated thermal cycling to cryogenic temperatures. Moisture, especially vapor, degrades film quality rapidly. These materials are stable to high temperatures in either N2 or O2 ambients. While total degradation, resulting from Tl depletion, occurs at the same temperatures for both phases, 600 °C in N2 and 700 °C in O2, the onset of degradation occurs at somewhat lower temperatures for TlBa2CaCu2O7 than for Tl2Ba2CaCu2O8.

High quality epitaxial thin films of actinide oxides, carbides, and nitrides: Advancing understanding of electronic structure of f-element materials

2014 ◽  
Vol 266-267 ◽  
pp. 137-154 ◽  
Author(s):  
Brian L. Scott ◽  
John J. Joyce ◽  
Tomasz D. Durakiewicz ◽  
Richard L. Martin ◽  
T. Mark McCleskey ◽  
...  
Keyword(s):  
Thin Films ◽  
Electronic Structure ◽  
Epitaxial Thin Films ◽  
High Quality ◽  
Actinide Oxides

(001) grain boundaries in Ag-clad Bi2Sr2Ca1Cu2O8+y (BSCCO) tapes

1991 ◽  
Vol 49 ◽  
pp. 1088-1089
Author(s):  
Y. Feng
Keyword(s):  
Grain Boundaries ◽  
Cuprate Superconductors ◽  
Weak Link ◽  
Weak Field ◽  
Weak Links ◽  
Great Promise ◽  
Core Thickness ◽  
Current Densities ◽  
Powder In Tube ◽  
Very High

Recently, Ag-clad tapes of Bi-cuprate superconductors have shown great promise for application as conductors in very high magnetic fields at temperature 4-20 K. High critical current densities (Jc) with weak field dependence indicate that the powder-in-tube process can drastically reduce the effect of grain boundary weak links at 4-20 K. It is thus of great interest to study the grain boundaries in the Ag-clad BSCCO tapes to understand their effect on the Jc.BSCCO Ag-clad wires with 2:2:1:2 starting composition were drawn and rolled to rectangular tapes (0.1 x 3 mm) with BSCCO core thickness of 45μm. The sample was heated at 920°C for 15 minutes, cooled to 840°C at 10°C/h, then annealed at 840°C for 70 h. The measured Jc values exceed 2x104 A/cm2 (5T, 4.2K) and do not exhibit obvious weak link behaviour. In order to investigate the (001) grain boundaries, samples were made by bonding several tapes together along their broad face. Thin longitudinal slices were cut and then ion milled at 4.5 kV in liquid nitrogen. TEM was carried out by using a JEOL 200CX-II at 200 kV.

Microstructure of thin YBa2Cu3O7−δ films

1990 ◽  
Vol 48 (4) ◽  
pp. 8-9
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Film Growth ◽  
Weak Link ◽  
Critical Currents ◽  
Weak Links ◽  
High Tc ◽  
Fundamental Interest ◽  
Early Stages ◽  
Transmission Electron ◽  
Patterned Films

The microstructure of superconducting thin-films often strongly influences their electrical properties. The actual microstructure of the film will be dependent on the nucleation and early stages of film growth, although the substrate will also be expected to exert an influence during the early stages of growth by the establishment of epitaxy. The highest critical currents have been obtained with films grown on SrTiO3, however MgO is of fundamental interest because patterned films on MgO have been shown to possess Josephson weak-link structure. The presence of the Josephson weak-links has been correlated with the occurrence of misaligned grains in films grown on MgO. Ultra-thin films of high-Tc superconductors are of interest for understanding the properties of these materials and may also be of use in technical applications.The microstructure of ultra-thin YBa2Cu3O7−δ films prepared by pulsed-laser ablation onto (001)- oriented MgO has been studied using transmission electron microscopy (TEM) and selected-area diffraction (SAD).

Effect of the Weak Links on the Surface Resistance of YBa2Cu3Ox Bulk Material

1992 ◽  
Vol 275 ◽  
Author(s):  
J. Wosik ◽  
L. M. Xie ◽  
J. Halbritter ◽  
R. Chau ◽  
A. Samaan ◽  
...  
Keyword(s):  
Surface Resistance ◽  
Weak Link ◽  
Bulk Material ◽  
Weak Links ◽  
Wave Surface ◽  
Critical Fields ◽  
High Quality ◽  
Dc Magnetic Field ◽  
Replacement Method ◽  
Field Temperature

ABSTRACTDc magnetic field, temperature, and magnetic history dependencies of the millimeter-wave surface resistance have been measured in high quality grain-aligned and in polycrystalline YBa2Cu3Ox bulk material. The measurements were carried at 75 GHz using the endplate of the cavity replacement method. The data is interpreted in terms of the presence of intra- and inter-grain types of weak links. The values of characteristic critical fields of the bulk and the weak link junctions are determined and discussed.

Grain Boundaries in Yba2 Cu3O7-δ Thin Films

1989 ◽  
Vol 169 ◽  
Author(s):  
M. Grant Norton ◽  
Lisa A. Tietz ◽  
C. Barry Carter ◽  
Stephen E Russek ◽  
Brian H. Moeckly ◽  
...  
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Grain Boundaries ◽  
Weak Link ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Superconducting Films ◽  
High Angle ◽  
Twin Boundaries

AbstractGrain boundaries in YBa2Cu3O7-δ thin films deposited on (001)-MgO by pulsed laser ablation have been characterized using selected area diffraction. In addition to twin boundaries, the presence of both low-angle and high-angle grain boundaries were characteristic of the film's microstructure. The presence of certain grain boundaries may be responsible for the weak-link Josephson behavior observed in small constrictions formed in superconducting films on MgO.

Sign in / Sign up

Export Citation Format

Share Document