EFFECT OF THE SECOND PHASE ON CRITICAL CURRENT DENSITY IN Nb-ADDED YBCO FILMS

1995 ◽  
Vol 09 (07) ◽  
pp. 439-443 ◽  
Author(s):  
JUN-HUI JIA ◽  
ZHEN-ZHONG QI
Keyword(s):  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Superconducting Films ◽  
Superconducting Phase ◽  
Second Phase ◽  
Dc Magnetron Sputtering ◽  
Ybco Films ◽  
Crystalline Substrate

Thin films of YBCO with or without Nb added were prepared on (100) ZrO 2 single crystalline substrate by dc magnetron sputtering method. A phase of YBa 2 NbO 6 was found to form not only in the target materials of YBCO but also in the sputtered thin films. The second phase of YBa 2 NbO 6 in the superconducting films destroyed a match relation between the lattice of YBCO and the lattice of ZrO 2 substrate. The measurements of critical current density J c under magnetic field (H // c axis, up to 5T) showed that the J c in Nb-added YBCO films reduced more apparently than that in YBCO films. It is concluded that the existence of second phase of YBa 2 NbO 6 in superconducting phase does not play a rule of flux pinning.

Thickness dependence of microstructure and critical current density of Yba2Cu3O7−δ on rolling-assisted biaxially textured substrates

2003 ◽  
Vol 18 (5) ◽  
pp. 1109-1122 ◽  
Author(s):  
K. J. Leonard ◽  
A. Goyal ◽  
D. M. Kroeger ◽  
J. W. Jones ◽  
S. Kang ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Ybco Film ◽  
Cube Texture ◽  
Film Surface ◽  
Second Phase ◽  
Film Properties ◽  
Cross Sectional ◽  
Ybco Films

The change in microstructure associated with the decrease in critical current density (Jc) of Yba2Cu3O7−δ (YBCO) films with increasing thickness was examined. Samples of pulse laser deposited YBCO films varying in thickness from 0.19 to 3.0 μm on rolling-assisted biaxially textured substrates with an architecture of CeO2/YSZ/CeO2/Ni were prepared by tripod polishing for cross-sectional electron microscopy. More randomly oriented grains in the upper portion of the YBCO film surface were observed with increasing film thickness, resulting in less cube texture. In addition, increases in mismatch across the boundaries of the c-axis grains with increasing time during deposition, along with the development of BaCeO3 and Y2BaCuO5 phases at the YBCO/CeO2 interface, contributed to the degradation of film properties. Surface outgrowths of the YBCO film were examined as well as the defect structures and second-phase formations within the films.

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.

Effects of surface damage on critical current density in MgB2 thin films

2021 ◽  
Vol 22 ◽  
pp. 14-19
Author(s):  
Soon-Gil Jung ◽  
Duong Pham ◽  
Jung Min Lee ◽  
Yoonseok Han ◽  
Won Nam Kang ◽  
...  
Keyword(s):  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Surface Damage ◽  
Mgb2 Thin Films

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.

Critical current density and flux pinning in Gd1−xYxBa2Cu3O7−y epitaxial thin films

1995 ◽  
Vol 250 (1-2) ◽  
pp. 55-58 ◽  
Author(s):  
R.L. Wang ◽  
H.C. Li ◽  
B. Yin ◽  
J.W. Li ◽  
X.S. Ron ◽  
...  
Keyword(s):  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Flux Pinning ◽  
Epitaxial Thin Films

Rapid and simple measurement of critical current density in HTS thin films using a permanent magnet method

2005 ◽  
Vol 426-431 ◽  
pp. 1122-1126 ◽  
Author(s):  
A. Saito ◽  
K. Takeishi ◽  
Y. Takano ◽  
T. Nakamura ◽  
M. Yokoo ◽  
...  
Keyword(s):  
Thin Films ◽  
Critical Current Density ◽  
Permanent Magnet ◽  
Critical Current ◽  
Current Density ◽  
Simple Measurement
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