• Progress in Superconductivity and Cryogenics
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• v.9 no.3
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• pp.9-12
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• 2007

In this study. we searched for the mechanical and electrical properties of laminated coated conductors with stabilizer tape. Stabilizer tape plays a role for mechanical and electrical stability and environmental protection. Cu material stabilizer was laminated to Ag capping layer on SmBCO conductor layer. This architecture allows the wire to meet operational requirements including the stressless at cryogenic temperature and winding tension as well as mechanical bending requirements including thermal and electrical stability under fault current conditions. First, we have experimentally studied mechanical bonding properties of the laminated Cu stabilizers on SmBCO coated conductors. We have laminated SmBCO coated conductors by continuous dipping soldering process, Second, we have investigated electrical properties of the SmBCO coated conductors with stabilizer lamination. We evaluated bonding properties, peeling strength and critical current for laminated SmBCO coated conductors with Cu stabilizers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.482-485
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• 2002

We synthesize a (Y,Sm)BCO(its composition is (Y/Sm123+0.4Y/Sm211)+1wt%CeO$_2$) powders using polymeric complex method. (Y,Sm)BCO powders are prepared as heated at 970$^{\circ}C$. For measurement of this characterization, We measure XRD and SEM. We use TSMG method for fabricatlon of (Y,Sm)BCO single crystal. The manufactured VBCO single crystal is measured by a magnetic distribution device using 0.5 Tesla magnet. As the result of this measurement, we find that a trapped magnet fields are 550 Gauss.

• Progress in Superconductivity
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• v.7 no.1
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• pp.77-82
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• 2005

We report a successful fabrication of high-quality $SmBa_{2}Cu_{3}O_{7-{\delta}}$ (SmBCO) thin films on $LaAlO_3$(LAO)(100) single crystalline substrates by a modified TFA-MOD method. After the pyrolysis heat treatment of spin-coated films up to $400^{\circ}C$, SmBCO films were fired at various temperatures ranging from 810 to $850^{\circ}C$ in a reduced oxygen atmosphere (10 ppm $O_2$ in Ar). Optimally processed SmBCO films exhibited the zero-resistance temperature ($T_{c,zero}$) of 90.2 K and the critical current density ($J_c$) of $0.8\;MA/cm^2$ at 77K in self-field. Compared with the $J_c$ values (normally, > $2\;MA/cm^2$ at 77 K) of MOD-TFA processed YBCO films, rather depressed $J_c$ values in SmBCO films are most probably attributed to the existence of ${\alpha}$-axis oriented grains.

• Progress in Superconductivity and Cryogenics
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• v.8 no.3
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• pp.9-12
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• 2006

Batch type co-evaporation EDDC (Evaporation using Drum in Dual Chambers) system was recently manufactured to fabricate 100m - long SmBCO superconducting coated conductor. As a preliminary study before the fabrication of long tape. short CC samples have been fabricated using the EDDC system and their crystal texture and $I_c$ properties were investigated. $1.2 {\mu}m$-thick SmBCO layers were deposited on $CeO_2/YSZ/CeO_2$ buffered Ni-W tapes. $I_c$ of 128A/cm-w and corresponding $J_c$ of $1.1 MA/cm^2$ at 77K in self-field were obtained for SmBCO CC tape. In-field property of SmBCO CC was confirmed to be better than that of YBCO deposited by PLD.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.30-31
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• 2006

We have fabricated SmBCO coated conductor on IBAD-MgO substrates using unique co-evaporation method. The batch type co-deposition system was specially designed and named as EDDC(evaporation using drum m dual chamber) that is possible to deposit superconducting layer with different composition ratio at low temperature of $700^{\circ}C$. In this study, we have investigated the influence of SmBCO phase composition and texture of IBAD-MgO template on the critical current density. We have changed the deposition rates of Sm, Ba and Cu during co-evaporation to examine the optimal composition ratio shown better critical current density. The composition ratio and surface morphology of SmBCO coated conductors were analyzed by the EDX and SEM, respectively. A higher critical current density was measured at superconducting phase composition ratio of Ba deficiency, Sm or Cu rich compared to the Sm1Ba2Cu3Ox stoichiometry.

• Progress in Superconductivity
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• v.13 no.1
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• pp.7-11
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• 2011

The effects of Sm:Ba:Cu composition ratio in SmBCO coated conductor on their superconducting properties were investigated. The SmBCO coated conductors were fabricated by reactive co-evaporation method using EDDC(Evaporation using Drum in Dual Chamber) system. In this system, we could obtain various samples with different composition ratios in a batch by the technique providing composition gradient at deposition zone. From the specimens prepared by EDDC system, we found that composition ratio is uniform parallel to the drum axis, but gradient along the circumferential direction of the drum. We installed a shield having parallelogram open area between the deposition chamber and the evaporation chamber in EDDC system, and attached a 30 cm long template, which is parallel to drum axis, onto the drum surface. In this configuration, we could obtain SmBCO coated conductors having a gradient composition along the length of template. We measured the composition ratios and surface morphologies with periodic interval by SEM and EDAX, and confirmed the profile of composition ratio. We also measured critical current using non-contact Hall probe critical current measurement system and thereby could plot composition ratio vs. critical current. The maximum critical current was obtained, and the surface morphology with the shape of roof tile was observed at the corresponding composition ratio of Sm:Ba:Cu = 1.01:1.99:4.87. It was also found that composition ratio had an effect on not only critical current but also surface morphology.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.6
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• pp.546-549
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• 2007

As a rule, high temperature superconducting coated conductors have multi-layered buffers consisting of seed, diffusion barrier and cap layers. Multi-buffer layer deposition requires longer fabrication time. This is one of main reasons which increases fabrication cost. Thus, single buffer layer deposition seems to be important for practical coated conductor process. In this study, a single layered buffer deposition of $CeO_2$ for low cost coated conductors has been tried using thermal evaporation technique. 100 nm-thick $CeO_2$ layers deposited by thermal evaporation were found to act as a diffusion layer. $1\;{\mu}m-thick$ SmBCO superconducting layers were deposited by thermal co-evaporation on the $CeO_2$ buffered Ni-5%W substrate. Critical current of 90 A/cm was obtained for the SmBCO coated conductors.

• Progress in Superconductivity and Cryogenics
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• v.8 no.3
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• pp.32-36
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• 2006

Simplification of the buffer architecture in the fabrication of coated conductors is required because the deposition of multi-layers leads to a longer production time and a higher cost of coated conductors. In this study, a single layered buffer deposition of $CeO_2$ for low cost coated conductors has been tried using thermal evaporation technique. l00nm-thick $CeO_2$ layers deposited by thermal evaporation were found to act as a diffusion layer. $0.4{\mu}m$-thick SmBCO superconducting layers were deposited by thermal co-evaporation on the $CeO_2$ buffered Ni-W substrate. Critical current of $55.4 A/cm^2$ was obtained for the SmBCO coated conductors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.241-241
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• 2007

We fabricated SmBCO coated conductors(CCs) on IBAD-MgO templates using co-evaporation method. IBAD-MgO templates consist of PLD-LMO/epi-MgO/IBAD-MgO/Ni-alloy and showed good in-plane texture of below FWHM 7 degree. Evaporation rates of Sm, Ba, and Cu were precisely controlled to get the optimum composition ratio after deposition process. To optimize the oxygen partial pressure of reaction region, wide range of the partial pressure was investigated from 1 mTorr to 15 mTorr. By reducing the oxygen partial pressure to 5mTorr, (103)grains in SmBCO layer have been increased. On the other hand, there were only (001)grains in SmBCO layer deposited at 15 mTorr $O_2$. Deposition temperature was also investigated from $600^{\circ}C\;to\;800^{\circ}C$ to make high Ic SmBCO CCs. SmBCO on IBAD MgO template showed that the Ic increased gradually at higher growth temperature to $800^{\circ}C$, which the highest Jc and Ic is $2.6\;MA/cm^2$ and 500 A/cm-w., respectively.

• Progress in Superconductivity and Cryogenics
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• v.15 no.4
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• pp.1-5
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• 2013

This paper reviews recent progress in research and development (R&D) of reactive co-evaporation for high performance REBCO coated conductors in Korea. Two types of reactive co-evaporation methods were developed for the deposition of SmBCO and GdBCO superconducting layers respectively on the IBAD (Ion Beam Assisted Deposition)-MgO template in the Korean coated conductor project. Batch type reactive co-evaporation equipment and its processing were developed for SmBCO coated conductors at Korea Electrotechnology Research Institute (KERI) in conjunction with the Korea Advanced Institute of Science and Technology (KAIST), and a very high critical current exceeding 1,000 A/cm at 77 K in the self field was achieved through the optimization of deposition parameters. Reel-to-reel type reactive co-evaporation processing with a high conversion rate was also developed, while long length GdBCO coated conductors have been routinely produced by SuNAM Co. The minimum critical current of 422 A/cm-w at 77 K in self field was confirmed for 1 km-long GdBCO tape.