• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2003년도 High Temperature Superconductivity Vol.XIII
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• pp.24-24
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• 2003

• 한국응용과학기술학회지
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• 제17권2호
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• pp.144-148
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• 2000

A modification of the sol-gel method to obtain phase pure superconducting oxides is described. The method starts from organic salts of yttrium, barium and copper, such as acetates, and avoids the sudden and uncontrollable decomposition of the organic fraction which occurs if nitrates are used as starting materials. The aqueous solution obtained with citric acid in an alkaline medium is concentrated under vacuum. The solid so prepared is decomposed at about $300^{\circ}C$ thus giving an oxide precursor containing well dispersed yttrium, barium and copper. Pyrolysis at 850 - $920^{\circ}C$ followed by oxygen annealing gives the superconducting orthorhombic 123 phase. The results of TGA/DTA of the precursor, as well as XRD, electrical and magnetic property measurements on the pyrolysis products are presented and discussed.

• 대한화학회지
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• 제36권6호
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• pp.818-823
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• 1992

Y, Er, Yb, Ba 및 Cu를 각각 포함하는 유기금속 화합물인 2-Ethylhexanoate 화합물을 합성하였다. 합성된 유기금속화합물들은 모두 공통용매에 녹아 균일혼합물을 형성하였으며 이들을 원료물질로 하여 고온초전도체 $YBa_2Cu_3O_{7-\delta}(Y_{123})$, $ErBa_2Cu_3O_{7-\delta}(Er_{123})$ 및 $YbBa_2Cu_3O_{7-\delta}(Yb_{123})$를 제조하였다. X-선 회절분석결과 이들은 단일상이 아니었으며 $YBa_2Cu_4O_8(Y_{124})$를 포함한 약간씩의 불순물상을 포함하고 있었고, 이것은 자화율 측정에서도 확인되었다. Ceramic method로 제조한 시료에 비하여 임계온도가 대체로 높았으며, 부피반자성자화율은 큰 변화가 없는 것으로 판단된다.

• Progress in Superconductivity
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• 제4권2호
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• pp.162-167
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• 2003

The critical current value of Bi-2223/Ag tape can be influenced by various factors. In particular, it was known that properties of precursor powders could affect the formation of Bi -2223 and grain growth rate of the same. Since, moistures and organic matters can easily contaminate the precursor powders of Bi-2223 tapes and degrade properties of superconductors, the precursor powders should be kept in optimal conditions to minimize contamination. In this study, the effect of moisture and organic matters has been investigated. A Bi-2223/Ag tape contaminated with a large amount of moisture and organic matter has been characterized by low critical current values and bubbling. It has been found that as the quantity of moisture increases, the Bi-2223 phases are formed at lower temperature and the amount of non-superconducting phase increases.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.169-169
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• 2012

The high-temperature superconductor YBa2Cu3O7-x (YBCO) have attached attentions because of a high superconducting transition temperature, low surface resistance, high superconducting critical current density (Jc), and superior superconducting capability under magnetic field. Moreover, the Jc of YBCO superconductors can be enhanced by adding impurities to the YBCO films for vortex-pinning. Understanding and controlling pinning centers are key factors to realize high Jc superconductors. We synthesized vertically-aligned ZnO nanorods on SrTiO3 (STO) substrates by catalyst-free metal-organic chemical vapor deposition (MOCVD), and subsequently, deposited YBCO films on the ZnO nanorods/STO templates using pulsed laser deposition (PLD). The various techniques were used to analyze the structural and interfacial properties of the YBCO/ZnO nanorods/STO hybrid structures. SEM, TEM, and XRD measurements demonstrated that YBCO films on ZnO nanorods/STO were well crystallized with the (001) orientation. EXAFS measurements from YBCO/ZnO nanorods/STO at Cu K edge demonstrated that the local structural properties around Cu atoms in YBCO were quite similar to those of YBCO/STO.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.112-115
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• 2000

In this work the results of the systematic investigations on the effect of organic addition by using polymer compound as starting materials on the superconducting properties of YBCO electrophoretic deposited films on silver substrate are presented. The characteristics of the films were examined by X-ray diffraction and SEM observation. Our results show that the adhesion and microstructure of these films are sensitive to the nature of polymer compounds and sintering conditions (electrophoretic deposition, drying and heat-treatment procedures). To develop optimum microstructures for samples processed in this manner it is necessary to have an understanding of how these processes affect the microstructure and hence the properties of ceramic superconductors.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.112-115
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• 2000

In this work the results of the systematic investigations on the effect of organic addition by using polymer compound as starting materials on the superconducting properties of YBCO electrophoretic deposited films on silver substrate are presented. The characteristics of the films were examined by X-ray diffraction and SEM observation. Our results show that the adhesion and microstructure of these films are sensitive to the nature of polymer compounds and sintering conditions (electrophoretic deposition, drying and heat-treatment procedures). To develop optimum microstructures for samples processed in this manner it is necessary to have an understanding of how these processes affect the microstructure and hence the properties of ceramic superconductors.