• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2001.02a
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• pp.6-8
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• 2001

We evaluated the degree of texture through depth of the superconductor core of Bi-Sr-Ca-Cu-O(BSCCO) superconductor tape. The degree of texture was characterized by pole figure analysis, indicating that the degree of texture varied significantly with depth of the superconductor core. It was observed that the degree of texture was higher near the interface than inside the superconducting core. Based on the result of degree of texture, the region near the interface is thought to carry significant current compared to that inside the core.

• Transactions on Electrical and Electronic Materials
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• v.3 no.2
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• pp.20-23
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• 2002

Temperature (T) dependence of the sheet resistance (R$\_$$\square$/) has been investigated an the c-axis oriented thin films of the (Bi2212/Bi2201) mixed crystal with different molar fractions. The R$\_$$\square$/-T superconducting characteristic deteriorated with reduction of the Bi2212 fraction, and almost disappears at 48 mol% where a superconductor-to-insulator transition too k place, with the resistance on the normal state, R$\_$N/, reaching 4.1 kΩka at 80 K. This R$\_$$\square$/ value is close to the universal quantum number, h/(2e)$_2$≡ 6.5 kΩ predicted by the Kosterlitz-Thouless (KT) transition theory. The R$\_$$\square$/-T characteristics of the 48 mol% thin film can be elucidated as a competitive process of KT transition brought about by charge or vortex in the two-dimensional layer structure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.10a
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• pp.40-44
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• 2000

$Bi_2Sr_2Ca_nCu_{n+1}O_y$($n{\geq}0$; BSCCO)thin film is fabricated via two different processes using an ion beam sputtering method i.e. co-deposition and layer-by-layer deposition. A single phase of Bi2212 can be fabricated via the co-deposition process. While it cannot be obtained by the layer-by-layer process. Ultra-low growth rate in our ion beam sputtering system brings out the difference in Bi element adsorption between the two processes and results in only 30% adsorption against total incident Bi amount by layer-by-layer deposition, in contrast to enough Bi adsorption by co-deposition.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.9
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• pp.796-800
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• 2000

Bi$_2$Sr$_2$Ca$_{n}$Cu$_{n+1}$ O$_{y}$(n$\geq$0; BSCCO) thin film is fabricated via two different processes using an ion beam sputtering method i.e. co-deposition and layer-by-layer deposition. A single phase of Bi2212 can be fabricated via the co-deposition process. While it cannot be obtained by the layer-by-layer process. Ultra-low growth rate in our ion beam sputtering system brings out the difference in Bi element adsorption between the two processes and results in only 30% adsorption against total incident Bi amount by layer-by-layer deposition, in contrast to enough Bi adsorption by co-deposition.on.n.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.203-205
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• 2003

Parallel wounded windings with BSCCO-2223 HTS tape for 1MVA HTS transformer were designed and prototype windings were fabricated in double pancake type. The parallel HTS tapes were transposed between the pancakes via non-superconducting joints because it is hard to make transpositions inside the pancake windings. The prototypes were wound using copper tape with same size as BSCCO-2223 tape, which will be used in 1MVA HTS transformer. The windings will be used for high voltage test and insulation test of the transformer Parallel HTS windings are going to be fabricated and tested for current distribution in near future.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.213-216
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• 1999

BSCCO thin films are fabricated via a co-deposition process by an ion beam sputtering with an ultra-low growth rate, and sticking coefficients of the respective elements are evaluated. The sticking coefficient of Bi element exhibits a characteristics temperature dependence : almost a constant value of 0.49 below 730$^{\circ}C$ and decreases linearly with temperature over 730$^{\circ}C$. This temperature dependence can be elucidated from the evaporation and sublimation rates of bismuth oxide, Bi$_2$O$_3$ from the film surface. It is considered that the liquid phase of the bismuth oxide plays an important role in the Bi(2212) phase formation in the co-deposition process.

• Progress in Superconductivity
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• v.3 no.1
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• pp.41-44
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• 2001

We report the current transport properties of a normal metal/organic conductor/ superconductor tunnel junction as a novel high- $T_{c}$ superconducting three terminal device. The organic copper (II) phthalocyanine (Cu-Pc) layer was used far a polaronic quasiparticle (QP) injector. The injection of polaronic QP from the Cu-Pc interlayer into a superconductor $Bi_2$$Sr_2$$CaCu_2$ $O_{8+}$ $\delta$/(BSCCO) thin film generated a substantially larger nonequilibrium effect as compared to the normal QP injection current. The tunneling spectroscopy of an Au/cu-PC/BSCCO junction exhibited a zero bias conductance peak which may be due to Andreev reflection at a Cu-Pc/d-wave superconductor junction.n..

• Proceedings of the KIEE Conference
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• summer
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• pp.851-853
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• 2004

This paper deals with current distribution analysis of the windings of a superconducting transformer with BSCCO-2223 High Tc Superconducting (HTS) tapes. Current distribution of HTS windings wound in parallel is analyzed by electromagnetic field analysis of finite element method and verified by experiments. For the sake of uniform current distribution, windings must be transposed so to make the impedances of each strands same. The parallel HTS tapes were transposed between the pancakes via non-superconducting joints because it is hard to make transpositions inside the pancake windings. In order to measure current distribution, test windings are fabricated and experimented for both transposed and non-transposed windings. We compared test results with calculated ones.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.270-271
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• 2005

A high Tc superconducting with a nominal composition of $Bi_2Sr_2Ca_2Cu_3O_Y$ was prepared by the citarte method. The solid precursor produced by the dehydration of the gel at $120^{\circ}C$ for 12h is not in the amorphous state as expected but in a crystalline state. X-ray diffraction peaks of nearly the same angular position as the peaks of high Tc phase were observed in the precursor. After pyrolysis at $400^{\circ}C$ and calcination at $840^{\circ}C$ for 4h, the (001)peak of the high Tc phase was cleary observed. Experimental results suggest that the intermediate phase formed before the formation of the superconducting phase may be the most important factro in determining whether it is easy to form the high Tc phase or not. because the nucleation barriers of the two superconducting phase may be altered by the variation of the crystal structures of those intermediate phase.

• Progress in Superconductivity and Cryogenics
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• v.12 no.4
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• pp.31-35
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• 2010

In superconducting magnet applications, winding methods of the superconducting magnet can be classified into a layer winding and a pancake winding. The superconducting magnet using high temperature superconductor (HTS) with rectangular shape is generally fabricated using the pancake winding method. On the other hand, low temperature superconducting (LTS) magnet may be wound by either a pancake winding or a layer winding. Compared with the layer winding, the pancake winding method has a merit of easy replacement of a damaged pancake module, but it also has a demerit of requirement of splicing between each double pancake modules. In this paper, we investigated characteristics of the layer and pancake winding methods using HTS. Six samples were wound out of BSCCO and Coated Conductors (CCs) by two winding methods and their characteristics were experimentally observed.