Critical Current Density and Microstructure of Yba2Cu3O7-X Films as a Function of Film Thickness

1989 ◽  
Vol 169 ◽  
Author(s):  
A. Mogro-Campero ◽  
L.G. Turner ◽  
E.L. Hall ◽  
N. Lewis
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Film Plane ◽  
Nominal Composition ◽  
Substrate Plane ◽  
Furnace Annealing ◽  
Cross Sectional ◽  
Continuous Layer ◽  
Transmission Electron

AbstractThin films of nominal composition YBa2Cu3O7‐x (YBCO) were produced on (100) SrTiO3 substrates by coevaporation and furnace annealing. Film thicknesses in the range of 0.2 to 2.4/μm were analyzed. Microstructural investigations by cross sectional transmission electron microscopy (TEM) reveal a continuous layer of about 0.4 μm thickness adjacent to the substrate with c‐axis normal to the substrate plane. In thicker films the remaining top portion has the c‐axis in the film plane. The critical current density (J ) at 77 K decreases with increasing thickness in the thickness range exceeding 0.4 μm, qualitatively consistent with the microstructural observations, but quantitatively inconsistent with a simple model based on the microstructural data.

Critical current density and microstructure variations in YBa2Cu3O7−x + BaSnO3 films with different concentrations of BaSnO3

2008 ◽  
Vol 23 (12) ◽  
pp. 3363-3369 ◽  
Author(s):  
C.V. Varanasi ◽  
J. Burke ◽  
L. Brunke ◽  
H. Wang ◽  
J.H. Lee ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Gradual Increase ◽  
Critical Transition ◽  
Critical Transition Temperature ◽  
Transmission Electron ◽  
Order Of Magnitude ◽  
High Fields ◽  
Magnitude Increase

Previous work on YBa2Cu3O7−x (YBCO) + BaSnO3 (BSO) films with a single composition showed significant critical current density (Jc) improvements at higher fields but lowered Jc in low fields. A detailed study on BSO concentrations provided here demonstrates that significant Jc enhancement can occur even up to 20 mol% BSO inclusion, where typical particulate inclusions in these concentrations degrade the YBCO performance. YBCO + BSO films were processed on (100) LaAlO3 substrates using premixed targets of YBa2Cu3O7-x (YBCO) with additions of 2, 4, 10, and 20 mol% BSO. The critical transition temperature Tc of the films remained high (>87 K), even with large amounts (20 mol%) of BSO. YBCO + BSO films showed a gradual increase in Jc at high fields as the amount of BSO was increased. More than an order of magnitude increase in Jc was measured in YBCO + BSO samples as compared to regular YBCO at 4 T. YBCO + 10 mol% BSO films showed overall improvement at all the field ranges while YBCO + 20 mol% BSO was better only at high fields. Transmission electron microscopy revealed the presence of ∼7–8-nm-diameter BSO nanocolumns, the density of which increased with increasing BSO content correlating well with the observed improvements in Jc.

Superconducting Properties of Bi1.6Pb0.4Sr2Ca2-xDyxCu3Oy Prepared via Co-Precipitation Method

2012 ◽  
Vol 622-623 ◽  
pp. 177-181 ◽  
Author(s):  
H. Azhan ◽  
J.S. Hawa ◽  
K. Azman ◽  
H.N. Hidayah ◽  
S.Y.S. Yusainee
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Volume Fraction ◽  
Resistivity Measurement ◽  
Xrd Analysis ◽  
Precipitation Method ◽  
Electrical Resistivity Measurement ◽  
Nominal Composition ◽  
Co Precipitation

The samples with nominal composition of Bi1.6Pb0.4Sr2Ca2-xDyxCu3Oywhere x = 0.000, 0.025, 0.050, 0.100 and 0.200 were prepared by the co-precipitation (COP) method. The samples were characterized by x-ray diffraction, electrical resistivity measurement and critical current density. The critical current density (JC) and superconductivity transition temperature (TC) of Dy substituted were found to be lower than the Dy-free sample. The TCvalues vary between 100 K and 75 K toward Dy concentration due to a small change of carrier concentration. The highest TC in Dy-doped sample was found at 96 K in x = 0.025. The JCdecreased towards Dy substitution, and it was measured to be 5751.2 mA/cm2 in Dy-free and 3769.8 mA/cm2in x = 0.025 at 77 K. XRD analysis showed the substitutions of Dy reduced the volume fraction of the 2223 phase and increased the volume fraction of the 2212 phase. The proportion of Bi-2223/Bi-2212 (%) were estimated from 76.74/23.26 in Dy free to 18.90/81.10 in x = 0.200.

Spatial variations in composition in high-critical-current-density Bi-2223 tapes

2000 ◽  
Vol 15 (2) ◽  
pp. 285-295 ◽  
Author(s):  
T. G. Holesinger ◽  
J. F. Bingert ◽  
M. Teplitsky ◽  
Q. Li ◽  
R. Parrella ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Compositional Analysis ◽  
Structural Features ◽  
Spatial Variations ◽  
High Critical Current Density ◽  
Transmission Electron ◽  
Filament Structure ◽  
Considerable Range

A detailed compositional analysis of high-critical-current-density (Jc) (55 and 65 kA/cm2at 77 K) (Bi,Pb)2Sr2Ca2Cu3Oy(Bi-2223) tapes was undertaken by energy dispersive spectroscopy in the transmission electron microscope. Structural features were coupled with characteristic compositions of the Bi-2223 phase. The average of all compositional measurements of the Bi-2223 phase was determined to be Bi1.88Pb0.23Sr1.96Ca1.95Cu2.98Oy. However, spatial variations in the Bi-2223 composition and differing phase equilibria were found throughout the filament structure. In particular, a considerable range of Bi-2223 compositions can be found within a single tape, and the lead content of the Bi-2223 phase is significantly depressed in the vicinity of lead-rich phases. The depletion of lead in the Bi-2223 phase around the 3221 phases may be a current-limiting microstructure in these tapes.

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.

TlBaCaCuO and YBaCuO superconductor thin films via an electrodeposition process

1991 ◽  
Vol 6 (7) ◽  
pp. 1389-1392 ◽  
Author(s):  
R.N. Bhattacharya ◽  
P.A. Parilla ◽  
A. Mason ◽  
L.L. Roybal ◽  
R.K. Ahrenkiel ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Film Plane ◽  
Zero Magnetic Field ◽  
Electrodeposition Process ◽  
Constant Potential ◽  
Zero Resistance ◽  
Potential Conditions

Thin-film superconductors of TlBaCaCuO (TBCCO) and YBaCuO (YBCO) were fabricated via an electrodeposition process. The precursors of the superconducting TBCCO films were codeposited at a constant potential of −4 V onto a silver-coated SrTiO3 substrate. The YBCO precursors also were codeposited but under pulsed-potential conditions (in order to improve the film morphology) and onto a silver-coated MgO substrate. The pulsed-potential cycle consisted of 1 s at −4 V followed by 1 s at −1 V. The post-annealed TBCCO film showed zero resistance at about 102 K and critical current density at 76 K of 20 000 A/cm2 in zero magnetic field and 5000 A/cm2 in a 10 kOe field parallel to the film plane. The post-annealed YBCO film showed zero resistance at approximately 80 K and critical current density of 5160 A/cm2 at 4 K in zero magnetic field.

EFFECT OF NANO-Y-ZrO2 ADDITION ON THE MICROSTRUCTURE AND CRITICAL CURRENT DENSITY OF MgB2 SUPERCONDUCTORS

2004 ◽  
Vol 03 (04n05) ◽  
pp. 563-569 ◽  
Author(s):  
Q. W. YAO ◽  
X. L. WANG ◽  
A. H. LI ◽  
S. X. DOU ◽  
P. R. MUNROE
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Magnetic Measurements ◽  
Transmission Electron ◽  
Long Time ◽  
Powder Addition ◽  
Short Time ◽  
Mgb2 Superconductors

Polycrystalline MgB 2 samples with 0, 5, 10, and 20 wt% nano- Y - ZrO 2 (YSZ) powder addition were prepared by short time, as little as several minutes, or long time in-situ reaction process. The phases, microstructures and flux pinning behaviors were characterized using X-ray diffractometry (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscope (TEM) and Magnetic Measurements. Results indicated that nano-YSZ particles included in MgB 2 grains. Samples doped with 10wt% YSZ powders showed new record of critical current density Jc as high as 1×106 and 4×106 A/cm 2 in low magnetic fields at 30 and 20K, respectively. However, the Jc drops faster compared to that made by long time sintering samples. It is proposed that the improved Jc in low fields was due to the enhanced density of the sample, which was caused by the YSZ nano-particle inclusion.

Impact of Eu Nanoparticles Substitution for Ca Site in Bi(Pb)-2223 Cuprates Superconductor

2020 ◽  
Vol 301 ◽  
pp. 202-208
Author(s):  
E.S. Nurbaisyatul ◽  
H. Azhan ◽  
Kasim Azman ◽  
Norazila Ibrahim ◽  
Siti Fatimah Saipuddin
Keyword(s):  
Critical Temperature ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Solid State Reaction Method ◽  
Nominal Composition ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Effective Surface ◽  
X Ray

The sample with nominal composition of Bi1.6Pb0.4Sr2Ca2-xEuxCu3Oy where x = 0.000, 0.0025, 0.020, 0.050 and 0.100 were synthesized through solid state reaction method. The effect of Eu2O3 nanoparticles doping on the superconducting and structural properties were studied by means of critical temperature, TC, critical current density, JC, X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The amount of 2223 phase gradually decreased with the increment of Eu concentration which indicates that Eu nanoparticles substitution at Ca site favours the growth of 2212 phases. The sample with higher porosity was found to be decreased in critical temperature, TC as well as critical current density, JC due to the lack of effective surface area for current flowing. The best superconducting properties were observed at x = 0.0025 substitutes into Ca site for Bi (Pb)-2223 host sample.

Sign in / Sign up

Export Citation Format

Share Document