• Progress in Superconductivity
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• v.7 no.2
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• pp.167-173
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• 2006

Coated conductors suitable for the fabrication of persistent mode high $T_c$ magnets are suggested and the fabrication method of persistent mode magnets using coated conductor are demonstrated. Persistent current was observed in a small piece of coated conductor. Closed loop of coated conductor with a diameter of around 1 em was successfully prepared and was cooled with a magnetic field of about 500 Gauss in order to induce supercurrent. Coated conductor with a $I_c$ of 100 A/cm-width was used for the preparation of closed loop of coated conductor. Persistent current was confirmed by measuring the magnetic field generated from closed loop of coated conductor by using Gauss meter. Magnetic field of 4.4 Gauss was detected from the supercurrent of closed loop of coated conductor. It shows that superconducting joint of coated conductor is not a prerequisite for the construction of persistent mode magnets. It is thought that this work opens the possibility to use coated conductor for the construction of persistent mode high $T_c$ magnets for MRI, NMR and magnetic separation applications.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.12
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• pp.1067-1072
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• 2009

YBCO coated conductor is named by second generation superconductor tapes. It is different with first generation superconductor tapes. YBCO coated conductor's specific difference with Bi-2223/Ag tape is more strong mechanical durability. This is important role to apply to superconducting machines. For mechanical transforming of YBCO coated conductors, we are using the well designed former. The merit of transformation is several. First, we vary the superconducting characteristics according to mechanical stress. Second, we reduce the volume of superconductor, so we achieve reducing the volume of superconducting machines. On this study, we experiment the transporting current characteristics of one types YBCO coated conductor. YBCO coated conductor with Ie of 70 A and voltage grade of 0.6 V/cm were connected to spiral former to conduct current application test.

• Progress in Superconductivity and Cryogenics
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• v.14 no.1
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• pp.4-7
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• 2012

Coated conductors have been developed to increase piece length and critical current for electric power applications. Otherwise, Many efforts were carried out to reduce AC loss of coated conductor for AC applications. Twisting and cabling processes are effective to reduce AC loss but, these processes can not be applied for tape shaped coated conductor. It is inevitable to have thin rectangular shape because coated conductor is fabricated by thin film deposition process on metal substrate. In this study, round shape superconducting wire was first fabricated using coated conductors. First of all, Ag coated conductor was used. coated conductor was slitted to several wires with narrow width below 1mm. 12ea slitted wires were parallel stacked on top of another until making up the square cross-section. The bundle of coated conductors was heat treated to stick on each other by diffusion bonding and then copper plated to make round shape wire. Critical current of round wire was measured 185A at 77K, self field.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.357-358
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• 2009

YBCO Coated Conductor is named by Second generation Superconductor Tapes. It is different with First generation Superconductor Tapes. YBCO Coated Tape's Specific difference with BSCCO Tape is more strong mechanical Durability. This is important role to apply to Superconducting Machines. For mechanical transforming of YBCO Coated Tapes, We are using the well designed former. The Merit of Transformation is several. First, We vary the Superconducting Characteristics according to mechanical stress. Second, We reduce the Volume of Superconductor, So We achieve reducing the volume of Superconducting Machines. On this Study, We experiment the transporting Current Characteristics of two types YBCO Coated Conductor. The one is Stainless Stabilized YBCO Conductor, and the other one is Copper Stabilized YBCO Conductor.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1285-1287
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• 2005

고온초전도 선재 중에서 YBCO 박막을 금속테이프에 증착하여 제조되는 coated conductor는 높은 자기장에서도 임계전류밀도의 감소가 크지 않아 고자장용 초전도 자석을 제조하는데 많이 활용될 것으로 기대되고 있다. coated conductor를 고자장용 초전도 자석제작에 활용하기 위해서는 긴 길이의 도체를 제조하는 것과 함께, 도체의 접합기술이 필요하다. 이는 초전도 자석을 영구전류모드로 운전하기 위해서는 도체의 접촉저항이 충분히 적어야 하기 때문이다. 그러나 박막형 coated conductor는 아직 긴 길이의 선재제조기술이 확립되어 있지 않고, 또 박막형 coated conductor의 형태와 사용되는 제조기술이 본질적으로 초전도 접합을 형성시키기에 매우 어려워서 아직 까지 초전도 접합에 대한 연구결과가 발표되지 않고 있으며, 접합 특성을 측정하는 기술도 개발되지 않았다. 본 연구에서는 coated conductor의 접합특성을 측정하기 위한 기본적인 시험방법을 제안하고, 전도성 금속접합재를 이용한 접합시료를 제작하여 그 특성을 평가한 결과를 발표한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.93-96
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• 2004

다층의 산화물 박막 구조를 갖는 coated conductor의 장선 제조를 위해서는 연속 증착 공정이 필요하다. 본 연구에서는 RABiTs와 IBAD 공정을 사용한 texture template을 사용하였으며, 금속 테잎을 연속적으로 이동하면서 증착할 수 있는 박막증착 장치(PLD, sputtering, evaporation)를 구축하여 PVD 방법으로 coated conductor를 제조하였다. $CeO_2/YSZ/Y_2O_3$의 완충층을 sputtering 과 evaporation을 이용하여 2축배향성을 가지는 NiW 위에 연속적으로 증착하였다. YBCO 초전도층은 연속 PLD 방법으로 증착하고, Tc, Ic, XRD, SEM을 통해 그 특성을 분석하였다. 그 결과 RABiTS template을 사용하여 Ic가 34A/cm(@77K)인 0.4m 길이의 coated conductor를 제조하였다. IBAD template를 사용하여 Ic가 34A/cm(@77K)인 0.5m길이의 coated conductor를 제조하였고, Jc는 $1.2MA/cm^2$ 이였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.211-211
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• 2009

YBCO coated conductor can change the stabilization layer for purpose and it leads advantages in Improvement of tape's critical properties and Application. Such properties rise possibility of using YBCO coated conductor for Superconductor Fault Current Limiter, therefore, we investigate changing properties under over current condition and limiting characteristics. In this study, YBCO coated conductor's current limiting characteristic stainless steel stabilization layer under condition of changing conductor's insulating layer. Consequently, the resistance followed insulating layer so we know that limiting characteristics.

• Progress in Superconductivity and Cryogenics
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• v.10 no.1
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• pp.52-56
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• 2008

According to the improvement of HTS conductor, HTS tapes which have the high current capacity have been recently researched in several nations. For large power application, AC loss is the most important issue in the development of AC superconducting power devices because it is closely related to the system operation efficiency. In 1st generation wire of HTS conductor, BSCCO, AC loss is too large to use for power application. Also, It is well known in recently years that YBCO CC, the 2nd generation wire, has also too much AC loss to apply to AC power devices. There are many trials to develop the new HTS wire having the low AC loss around the world. In this research, we present the measurment result of magnetization losses in SmBCO coated conductors. We measured the magnetization loss generated by perpendicularly exposed external magnetic field and compared with the analytic value of the strip model. Also, we presented the results compared with measured magnetization loss of an YBCO coated conductor.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.10
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• pp.788-792
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• 2010

The yttrium-barium-copper-oxide (YBCO) coated conductor, which supplement the fault of the existing superconducting current-limit materials YBCO thin film, bismuth-strontium-calcium-copper-oxide(BSCCO) wire and bulk, has been improved its mechanical weakness and has high index; hence, after quench YBCO coated conductor could limit the fault current effectively because of fast resistance occurrence speed. Furthermore, it has wide applicable area as an current limit material because it shows different resistance occurrence tendency by the thickness and kind of stabilization material sputtered on the superconducting layer. Therefore, many researchers are carrying out the study of application of YBCO coated conductor to superconducting fault current limiter (SFCL) for making high quality current limit element, based on resistance type. On the other hand, the study for other type except resistance type has been rarely conducted for the application of YBCO coated conductor to SFCL as an current limit element. Consequently, in this study, YBCO coated conductor with different stabilization layer Cu and Stainless steel, is applied to SFCL using iron core and coil, and examine the many index points as an current limit element, such as current limit characteristic, the tendency of resistance occurrence, response time, the temperature trend for stability.

• 한국초전도학회:학술대회논문집
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• 2009.07a
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• pp.86-86
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• 2009