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Title: High critical current density Bi 2 Sr 2 CaCu 2 O x /Ag wire containing oxide precursor synthesized from nano-oxides

Authors:
; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1286295
Grant/Contract Number:
SC0009705
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Superconductor Science and Technology
Additional Journal Information:
Journal Volume: 29; Journal Issue: 9; Related Information: CHORUS Timestamp: 2016-08-09 03:26:56; Journal ID: ISSN 0953-2048
Publisher:
IOP Publishing
Country of Publication:
United Kingdom
Language:
English

Citation Formats

Zhang, Yun, Johnson, Stephen, Naderi, Golsa, Chaubal, Manasi, Hunt, Andrew, and Schwartz, Justin. High critical current density Bi 2 Sr 2 CaCu 2 O x /Ag wire containing oxide precursor synthesized from nano-oxides. United Kingdom: N. p., 2016. Web. doi:10.1088/0953-2048/29/9/095012.
Zhang, Yun, Johnson, Stephen, Naderi, Golsa, Chaubal, Manasi, Hunt, Andrew, & Schwartz, Justin. High critical current density Bi 2 Sr 2 CaCu 2 O x /Ag wire containing oxide precursor synthesized from nano-oxides. United Kingdom. doi:10.1088/0953-2048/29/9/095012.
Zhang, Yun, Johnson, Stephen, Naderi, Golsa, Chaubal, Manasi, Hunt, Andrew, and Schwartz, Justin. 2016. "High critical current density Bi 2 Sr 2 CaCu 2 O x /Ag wire containing oxide precursor synthesized from nano-oxides". United Kingdom. doi:10.1088/0953-2048/29/9/095012.
@article{osti_1286295,
title = {High critical current density Bi 2 Sr 2 CaCu 2 O x /Ag wire containing oxide precursor synthesized from nano-oxides},
author = {Zhang, Yun and Johnson, Stephen and Naderi, Golsa and Chaubal, Manasi and Hunt, Andrew and Schwartz, Justin},
abstractNote = {},
doi = {10.1088/0953-2048/29/9/095012},
journal = {Superconductor Science and Technology},
number = 9,
volume = 29,
place = {United Kingdom},
year = 2016,
month = 8
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1088/0953-2048/29/9/095012

Citation Metrics:
Cited by: 2works
Citation information provided by
Web of Science

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  • Precursor powder composition is known to strongly affect the critical current density (J c) of Ag/Bimore » $$_2$$Sr$$_2$$CaCu$$_2$$O$$_x$$ (Bi-2212) wires. However, reasons for such J c dependence have not yet been fully understood, compromising our ability to achieve further optimization. In this paper, we systematically examined superconducting properties, microstructural evolution and phase transformation, and grain boundaries of Bi-2212 conductors fabricated from precursor powders with a range of compositions using a combination of transport-current measurements, a quench technique to freeze microstructures at high temperatures during heat treatment, and scanning transmission electron microscopy (STEM). Samples include both dip-coated tapes and round wires, among which a commercial round wire carries a high J c of 7600 A mm -2 at 4.2 K, self-field and 2600 A mm -2 at 4.2 K, 20 T, respectively. In the melt, this high-J c conductor, made using a composition of Bi 2.17Sr 1.94Ca 0.89Cu 2O x, contains a uniform dispersion of fine alkaline-earth cuprate (AEC) and copper-free solid phases, whereas several low-J c conductors contain large AEC particles. Such significant differences in the phase morphologies in the melt are accompanied by a drastic difference in the formation kinetics of Bi-2212 during recrystallization cooling. STEM studies show that Bi-2212 grain colonies in the high-J c conductors have a high density of Bi 2Sr 2CuO y (Bi-2201) intergrowths, whereas a low-J c conductor, made using Bi 2.14Sr 1.66Ca 1.24Cu 1.96O x , is nearly free of them. STEM investigation shows grain boundaries in low-J c conductors are often insulated with a Bi-rich amorphous phase. Finally, high-J c conductors also show higher flux-pinning strength, which we ascribe to their higher Bi-2201 intergrowth density.« less
  • The flux density distributions in sintered Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x} high-{Tc} superconducting specimens were observed by means of a magneto optic method using iron garnet films. The samples were formed into discs with thicknesses of 60 to 600 {mu}m and a diameter of 1.5 mm. SEM images showed that specimens consisted of grains with diameters of order 300 {mu}m. Flux penetrated inhomogeneously into specimens of thickness smaller than the grain diameters. However, flux penetration became homogeneous as the thickness was increased. Preferential flux penetration at grain boundaries was not observed in all specimens. The value of the critical currentmore » density, estimated from the flux penetration distance using Bean`s model applied to disc-shaped specimens, was about 10{sup 4} A/cm{sup 2} at 30K, which is nearly equal to the value estimated from the magnetization assuming that the shielding current flows uniformly through the entire specimen.« less
  • We demonstrate high critical current density superconducting films of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) and Tl{sub 2}Ba{sub 2}CaCu{sub 2}O{sub 8{minus}{delta}} (Tl-2212) using LaNiO{sub 3} (LNO) buffer layers. YBCO films grown on an LNO buffer layer have only a slightly lower J{sub c} (5K, H=0) than films grown directly on a bare LaAlO{sub 3} substrate. It is noteworthy that YBCO films grown on LNO buffer layers exhibit minor microstructural disorder and enhanced flux pinning. LNO-buffered Tl-2212 samples show large reductions in J{sub c} at all temperatures and fields compared to those grown on bare LaAlO{sub 3}, correlating to both a-axis grainmore » and nonsuperconducting phase formation. With additional optimization, LNO could be a promising buffer layer for both YBCO and Tl-based superconducting films, perhaps ideally suited for coated conductor applications.« less
  • Critical-current density (J{sub c}) is a parameter of primary importance for potential applications of high-temperature copper oxide superconductors. It is limited principally by the breakdown of zero-resistive current due to thermally activated flux flow at high temperatures and high magnetic fields. One promising method to overcome this limitation is to introduce efficient pinning centers into crystals that can suppress the flux flow. A marked increase in J{sub c} was observed in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} (Bi-2212) single crystals doped with a large amount of Pb. By electron microscopy, characteristic microstructures were revealed that probably underlie the observed enhancement inmore » J{sub c}: thin (10 to 50 nanometers), platelike domains having a modulation-free structure appeared with spacings of 50 to 100 manometers along the b axis. 30 refs., 4 figs.« less