Influence of nano-Cu additive on MgB2 phase formation, processing temperature, and transport properties

In this work, the effect of nano-sized SnO2 addition on the phase formation and electrical transport properties of (Tl0.85Cr0.15)Sr2CaCu2O7-δ (Tl-1212) superconductor was investigated. Thallium-based high temperature superconductor (HTS) with nominal starting composition (Tl0.85Cr0.15) Sr2CaCu2O7-δ was prepared using high purity oxide powders via solid state reaction method. Nano-sized SnO2 with 0.01 – 0.05 wt.% were added into Tl-1212 superconductors. The characteristic of the samples were determined by powder X-ray diffraction method (XRD), scanning electron microscopy (SEM), energy dispersive X-Ray analysis (EDX), electrical resistance measurements and transport critical current density measurements. Nano-sized SnO2 added (Tl0.85Cr0.15)Sr2CaCu2O7-δ showed Tc-zero between 93 and 95 K. All of the samples indicated a dominant phase of Tl-1212 with a minor phase of Tl-1201. The highest Jc (at 77 K) was shown by sample with 0.03 wt.% at 3260 mA/cm2. SnO2 has significantly enhanced the transport critical current density of Tl-1212 superconductor by acting as flux pinning centers. However, further addition of nano-sized SnO2 in Tl-1212 superconductor caused degradation in Jc. The SEM micrographs with energy dispersive X-Ray analysis (EDX) showed that SnO2 were well distributed in all the samples.

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The effect of starting precursor conditions on the phase formation and transport properties of Bi-2223/Ag tapes

Physica C Superconductivity ◽

10.1016/s0921-4534(02)02252-9 ◽

2003 ◽

Vol 386 ◽

pp. 186-189 ◽

Cited By ~ 1

Author(s):

C Jiang

Keyword(s):

Transport Properties ◽

Phase Formation

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Effects of Conversion Parameters on the Transport Properties of YBCO Films in the BaF2 Ex Situ Process

Journal of Materials Research ◽

10.1557/jmr.2004.0166 ◽

2004 ◽

Vol 19 (4) ◽

pp. 1281-1289 ◽

Cited By ~ 7

Author(s):

J. Yoo ◽

K.J. Leonard ◽

D.F. Lee ◽

H.S. Hsu ◽

L. Heatherly ◽

...

Keyword(s):

Water Vapor ◽

Transport Properties ◽

Buffer Layer ◽

Dwell Time ◽

Ex Situ ◽

Precursor Film ◽

Processing Temperature ◽

Vapor Pressures ◽

Ybco Films ◽

Conversion Time

The effects of conversion parameters on transport properties of YBa2Cu3O7-δ (YBCO) films on rolling assisted biaxially textured substrates (RABiTS) in the BaF2 ex situ process were investigated for total pressures Ptotal between 0.1 and 1.3 atm, water vapor pressures PH2O between approximately 7 and 70 Torr and processing temperatures TS between 700 and 790 °C. For this study, a 0.3-μm-thick Y–BaF2–Cu–O precursor film was deposited on a 1-cm-wide Ni=3 at.% W RABiTS with a buffer layer architecture of CeO2/YSZ/Y2O3/Ni deposited in single passes in various reel-to-reel systems for each layer. Under the conditions of Ptotal = 0.1 atm, TS = 740 °C and PO2 approximately 150 mTorr, JC > 2 MA/cm2 was obtained at 77 K and self field for PH2O ≤ 20 Torr. At higher PH2O (=70 Torr), however, the maximum attainable JC decreased. In addition, the JC at these higher PH2O dropped rapidly with increased dwell time. The highest JC, 2.5 MA/cm2, was achieved at 730 °C with Ptotal = 0.1 atm and PH2O approximately 7 Torr. Finally, the variation of IC with wet conversion time was performed at each processing temperature.

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