• Progress in Superconductivity and Cryogenics
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• v.9 no.4
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• pp.7-10
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• 2007

The transport current distribution across the tape width of a SmBCO coated conductor was investigated. The current distribution was estimated by applying an inversion process to the field distribution measured in the vicinity of the tape by using a scanning Hall probe method. The obtained result is well consistent with one predicted by the Bean model, however, at the edges the current are not constant and do not generally plateau, on the contrary.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.261-262
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• 2006

High temperature superconducting coated conductor has multi-layer structure of protecting layer/superconducting layer/buffer layer/metallic substrate. The buffer layer consists of multi layer, and the architecture most widely used in RABiTS approach is $CeO_2$(cap layer)/YSZ(diffusion barrier layer)/$CeO_2$(seed layer). Multi-buffer layer deposition required many times and process. Therefore single buffer layer deposition study reduce 2G HTS manufacture efforts. Evaporation technique for single buffer deposition method is used for the $CeO_2$ layer. $CeO_2$ single buffer film could be achieved in the chamber. Detailed deposition conditions (temperature and partial gas pressure of deposition) were investigated for the rapid growth of high quality $CeO_2$ single buffer film.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.11
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• pp.2209-2213
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• 2009

$REBa_{2}Cu_{3}O_{7-d}$(REBCO) coated conductors(REBCO CCs) have been studied for electric power applications which require high current density wires. As long as the critical transition temperature(Tc) is concerned, REBCO CCs with large $RE^{3+}$ ions have been expected to have better current transport properties than those with smaller $RE^{3+}$ ions. For this reason, REBCO's with large $RE^{3+}$ ions which include GdBCO, NdBCO and SmBCO have been mainly considered as the superconducting layer of CCs. On the other hand, REBCO's with smaller $RE^{3+}$ions are expected to have advantages in the fabrication process of CCs because of the lower melting temperature. But it has not yet been made clear which REBCO is the most suitable for the superconducting layer of CCs. In this study, we investigated the current transport properties of REBCO CCs with small $RE^{3+}$ ion and advantages of using that in the CC fabrication process. Thin films of TmBCO, which has smaller $RE^{3+}$ion than most other $RE^{3+}$ ions, were fabricated on buffered metal substrate as the superconducting layer of CC by PLD process. TmBCO CC shows critical current density (Jc (77 K, sf) = $2.3\;MA/cm^2$) high enough to be utilized for application in electric power devices. Compared with previous experiments using the same PLD system, deposition temperature was approximately $20^{\circ}C$ lower than NdBCO thin films on buffered metal substrates.

• 한국초전도학회:학술대회논문집
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• 2009.07a
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• pp.83-83
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• 2009

• 한국초전도학회:학술대회논문집
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• v.15
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• pp.76-76
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• 2005

• 한국초전도학회:학술대회논문집
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• v.12
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• pp.63-63
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• 2002

• Progress in Superconductivity and Cryogenics
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• v.9 no.4
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• pp.19-23
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• 2007

The superconducting properties of several HTS coated conductors (CC), which had different tape structures, fabricated by KERI, X and Y institutes were compared. We have fabricated the $high-J_c$ SmBCO CC, which has 273.5 A/cm, $1.2MA/cm^2$ and 93.5 K for $I_C,\;J_C\;and\;T_{c-zero}$, respectively, using the EDDC (Evaporation using Drum in Dual Chambers) process. Both X and Y institutes CCs, however, were purchased. The n-values of KERI, X and Y institutes CCs are 58.5, 40.7 and 31.5 in $V=1{\sim}10{\mu}V$ criterion, respectively. The in-field properties of $I_C$ at 77K were investigated and the $J_C(B)/J_C(0G)$ at 0.5 T with $B{\perp}$ ab-plane are 0.31, 0.19 and 0.24 for KERI, X and Y institutes CCs, respectively. From the $I_C-{\theta}-B$ measurement, we observed that the ab-plane of ReBCO phase was tilted for the ab-plane of substrate in the KERI and X institutes CCs. The tilted angle is about 5 degree. We confirmed that the peak shift (as an inclined texture) was observed by X-ray (102) pole figures of the SmBCO for the KERI CC.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.294-294
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• 2008

동시 증발 증착법 화합물의 구성원자를 독립적으로 증발시켜서 기판에 증착하는 방법이다. 각 물질은 온도에 따른 증기압을 가지는데 각 물질의 온도를 조절하여 증착률을 조절한다. 보트에서 떠난 원자가 기판에 도달할 확률은 챔버의 진공도, 보토와 기판과의 거리 등에 의하여 영향을 받는다. 진공도가 나쁠수록, 보트와 기판과의 거리가 멀수록 기판에 도달할 확률이 떨어진다. 동시증발 증착법을 이용한 SmBCO 초전도층 증착에서 각 물질의 기판에 도달하는 원자비를 조절하기 위하여 QCM(증착률 측정장치), QCM 가이드를 사용하였다. QCM sensor 입구에 튜브형태의 QCM 가이드를 설치하고 QCM 가이드가 특정한 물질의 증발보트를 향하도록 배치하였다. 따라서 각 보트에서 떠난 원자들은 특정한 QCM sensor에 도달하게 되고 결국 3원소(Sm, Ba, Cu)의 증착률의 비를 조절함으로써 조성비를 조절할 수 있게 된다. QCM 증착률의 비와 실제 조성비는 여러 가지 변수에 의하여 영향을 받는 다. 대표적인 변수는 챔버의 진공도, QCM 가이드의 직경 및 길이, QCM 센서와 보트와의 거리 등이 있다. 진공도가 높을수록 특정 보트에서 떠난 원자들이 QCM 가이드 입구에 도달할 확률이 낮아지고, QCM 가이드의 직경이 좁을수록 가이드 내벽에 흡착될 확률이 높아진다. 또한 QCM센서와 보트와의 거리가 멀수록 챔버내 잔류가스의 원자들과 충돌확률이 높아지므로 도달확률이 줄어들게 된다. 동시 증발 증확법에서 조성비의 재현성을 높이기 위해서는 매회 증착실험에서 진공도가 일정해야 하며, QCM 가이드와 보트와의 거리를 되도록 최소화 하고, QCM 직경을 크게 하는 것이 유리하다.

• 한국초전도학회:학술대회논문집
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• v.16
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• pp.74-74
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• 2006

• 한국초전도학회:학술대회논문집
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• v.16
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• pp.91-91
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• 2006