• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.10a
• /
• pp.150-152
• /
• 2003

YBa$_2$Cu$_3$O$_{7-{\delta}}$(YBCO) coated conductors were deposited by pulsed laser deposition (PLD) on short buffered substrate in continuous PLD reel-to-reel system. The oxide multilayer buffered substrate of architectures of CeO$_2$/YSZ/Y$_2$O$_3$was fabricated by PLD at steady status. The degree of texture of each layer was investigated using X-ray diffraction including $\theta$-2$\theta$ scans, $\omega$-scans and $\Phi$-scans analysis. Their surface morphology was observed by scanning electron microscopy (SEM) The FWHM of the X-ray $\omega$-scans and $\Phi$-scans indicated that YBCO and buffer layers closely replicate the in-plane and out-of-plane texture of metal tape. Critical current at 77K self-field of 19A, critical temperature of 86K, and current density of 2MA/$\textrm{cm}^2$ were measured. The film also exhibits a homogeneous and dense surface morphology.e morphology.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.12a
• /
• pp.107-108
• /
• 2006

High $J_c$ $YBa_2Cu_3O_x$, superconducting films were fabricated by MOD method using fluorine-free dichloroacetic acid(DCA) as chelating solvent for preparing precursor solution. DCA-MOD precursor solution was coated on a single crystal (001) $LaAlO_3$(LAO) substrate by a dip coating method with a speed of 25 mm/min. Coated films were calcined at lower temperature up to $500^{\circ}C$ and Conversion heat treatment was performed at various temperatures of $780{\sim}810^{\circ}C$. SEM observations showed that films have very dense microstructures for the films prepared at the temperature higher than $800^{\circ}C$ regardless of diluting solvent; methanol or 2-methoxyethanol. A High critical current density ($J_c$) of 1.28 $MA/cm^2$ (@77 K and self-field) was obtained for the YBCO film prepared using 2-methoxyethanol as a solvent.

• 한국초전도학회:학술대회논문집
• /
• v.10
• /
• pp.86-91
• /
• 2000

Ni tapes were textured by taking advantage of their secondary recrystallization. The obtained 18cm long tapes had textures of single crystalline qualities with their [001] axes tilted with respect to the surface and their [010] axes parallel to the rolling direction. YBCO/CeO$_2$/YSZ/CeO$_2$ films grown on the Ni tape had the same crystalline orientations. Magnetic field dependent I-V relations were measured on a 5cm section of the tape. Jc defined by 1mV criterion was 1.5 ${\times}$ 10$^5$A/cm$^2$ at 77K under zero field and was reduced by ${\sim}$50% under the applied magnetic field of 5T.

• Progress in Superconductivity
• /
• v.2 no.1
• /
• pp.33-38
• /
• 2000

Ni tapes were textured by taking advantage of their secondary recrystallization. The obtained 18cm long tapes had textures of single crystalline qualities with their [001] axes tilted with respect to the surface and their [010] axes parallel to the rolling direction. The reproducibility of this texturing was checked by taking statistics on the crystal orientations of 24 Ni tapes. $YBCO/CeO_2/YSZ/CeO_2$ films grown on the Ni tape had the same crystalline orientations. Magnetic field dependent I-V relations were measured on a 5cm section of the tape. $J_c$ defined by $20{\mu}V/mm$ criterion was $1.5\times10^5A/cm^2$ at 77K under zero field and was reduced by $\sim$50% under the applied magnetic field of 5T.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.11
• /
• pp.1241-1245
• /
• 2004

Continuous physical vapor deposition (PVD) method is one of many processes to fabricate long length coated conductor which is required for successful large-scale application of superconducting power devices. Three film deposition systems (pulsed laser deposition, sputtering, and evaporation) equipped with reel-to-reel(R2R) metal tape moving apparatus were installed and used to deposit multi-layer oxide thin films. Both RABiTS and IBAD texture templates are used. IBAD template consists of CeO$_2$(PLD)/YSZ(IBAD) on stainless steel(SS) metal tape, and RABiTS template has the structure of CeO$_2$/YSZ/Y$_2$O$_3$ which was continuously deposited on Ni-alloy tape using R$_2$R evaporation and DC reactive sputtering in a deposition system designed to do both processes. 0.4 m-long coated conductor with Ic(77 K) of 34 A/cm was fabricated using RABiTS template. 0.5 m and 1.1 m-long coated conductor with Ic(77 K) of 41 A/cm and 26 A/cm were fabricated using IBAD template.

• Progress in Superconductivity and Cryogenics
• /
• v.5 no.3
• /
• pp.23-25
• /
• 2003

Effect of chemically modified precursor solution on YBCO coated conductor prepared by MOD-TFA method was investigated. YBCO thin films were deposited on (l00)-oriented single crystalline LaAlO$_3$ substrates by conventional MOD-TFA process. The microstructures of YBCO thin films contain maze-like patterns. The origin of this microstructure was delineated by compositional inhomogeneity during the pyrolysis process and it was shown that addition of diethanolamine (DEA) improve the microstructure of grown YBCO films. In addition, it was demonstrated that the chemical modification of precursor solution makes no harmful effect on biaxial texture of YBCO thin films.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.10a
• /
• pp.79-82
• /
• 2003

We prepared YBCO coated conductor by direct deposition of YBCO on Ag substrate by a MOCVD method. The Ag substrate was only prepared by cold rolling. The XRD data of the as-rolled Ag tape showed the formation of dominant (420) oriented grains. Processing variables were the oxygen partial pressure (Po$_2$) and deposition temperature (T$_{d}$). It was found that the a-axis oriented films were grown at lower T$_{d}$ below 80$0^{\circ}C$, while the c-axis oriented films were grown about 80$0^{\circ}C$. The surface of the films consisted of a second inclusion phase dispersed in the YBCO matrix. The Cu-rich phase regions were observed at the YBCO/Ag interface probably due to the inter-diffusion of Ag and Cu. Cu.

• Progress in Superconductivity and Cryogenics
• /
• v.6 no.3
• /
• pp.12-15
• /
• 2004

There are two major approaches to obtain texture template for HTS coated conductor (CC) ---IBAD and RABiTS. CC's with IBAD template showed both longer and higher Ic results so far. IBAD for CC began with YSZ, the processing of which is very slow compared to other processings needed for the fabrication of CC. Because of this very slow processing speed, IBAD with other materials such as Gd$_2$Zr$_2$O$_{7}$(GZO) and MgO have been developed. The processings of IBAD-GZO and IBAD-MgO are known to be up to 3times and 100 times. respectively, as fast as the processing of IBAD-YSZ. IBAD-MgO is very attractive in that the processing is very fast. IBAD-MgO also needs additional buffer layer(s). Many materials are being investigated to be used as a buffer layer on top of the MgO. BaZrO$_3$ (BZO) is a good candidate as the buffer layer on top of the IBAD-MgO because it is chemically stable and does not react with YBCO at high temperatures. It also has good lattice match with MgO. The BZO film has been deposited on single crystal MgO, and YBCO film was deposited on BZO/MgO to investigate the possibility of using BZO as both the buffer and capping layer of the CC.C.

• 한국초전도학회:학술대회논문집
• /
• v.16
• /
• pp.75-75
• /
• 2006

• 한국초전도학회:학술대회논문집
• /
• v.14
• /
• pp.91-91
• /
• 2004