• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.371-373
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• 1998

The SmBa$_2$Cu$_3$O$\sub$x/ single crystals were used as seeds to induced YBCO growth in MTG process. As the result, the large bulk oriented YBCO superconductors were prepared with dimension of plane 21mm and 32mm in diameter and 10mm in height. The typical Jc value of the sample is 6.5${\times}$10$^4$A/$\textrm{cm}^2$ and its flux float force is 4.6N/$\textrm{cm}^2$. The oxygen absorption in large bulk textured YBCO samples in pure oxygen was studied at several constant temperatures. It can be divided into two steps: a chemical reaction step and a diffusion step.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.491-493
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• 1998

The SmBa$_2$Cu$_3$O$\sub$x/ single crystals were used as seeds to induced YBCO growth in MTG process. As the result, the large bulk oriented YBCO superconductors were prepared with dimension of plane 21mm and 32mm in diameter and 10mm in height. The typical Jc value of the sample is 6.5${\times}$10$^4$A/$\textrm{cm}^2$ and its flux float force is 4.6N/$\textrm{cm}^2$. The oxygen absorption in large bulk textured YBCO samples in pure oxygen was studied at several constant temperatures. It can be divided into two steps: a chemical reaction step and a diffusion step.

• Progress in Superconductivity and Cryogenics
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• v.13 no.1
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• pp.1-5
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• 2011

[ $CeO_2$ ]has been widely used for single buffer layer of coated conductor because of superior chemical and structural compatibility with $ReBa_2Cu_3O_{7-{\delta}}$(Re=Y, Nd, Sm, Gd, Dy, Ho, etc.). But, the surface of $CeO_2$ layer showed cracks because of the large difference in thermal expansion coefficient between metal substrate and deposited $CeO_2$ layer, when thickness of $CeO_2$ layer exceeds 100 nm on the biaxially textured Ni-3%W substrate. The deposition rate has been limited to be less than 6 $\AA$/sec in order to get a good epitaxy. In this research, we deposited $CeO_2$ single buffer layers on biaxially textured Ni-3%W substrate with 2-step process such as thin nucleation layer(>10 nm) with low deposition rate(3 $\AA$/sec) and thick homo epitaxial layer(>240 nm) with high deposition rate(30 $\AA$/sec). Effect of deposition temperature on degree of texture development was tested. Thick homo epitaxial $CeO_2$ layer with good texture without crack was obtained at $600^{\circ}C$, which has ${\Delta}{\phi}$ value of $6.2^{\circ}$, ${\Delta}{\omega}$ value of $4.3^{\circ}$ and average surface roughness(Ra) of 7.2 nm within $10{\mu}m{\times}10{\mu}m$ area. This result shows the possibility of preparing advanced Ni substrate with simplified architecture of single $CeO_2$ layer for low cost coated conductor.

• Economic and Environmental Geology
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• v.25 no.1
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• pp.27-39
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• 1992

Several pyrophyllite deposits occur around the Milyang area where Cretaceous andesitic rocks and spatially related granitic rocks are widely distributed. Pyrophyllite ores consist mainly of pyrophyllite, and quartz with small amount of sericite, pyrite, dumortierite, and diaspore. The andesitic rocks and spatially related granitic rocks in this area suggest that they could be formed from the same series of a calc-alkaline magma series. The contents of $SiO_2$, $Al_2O_3$, LOI(loss on ignition) are enriched, and $K_2O$, $Na_2O$, CaO, MgO, $Fe_2O_3$ are depleted in altered andesitic rocks and ores. Enrichment of As, Cr, Sr, V, Sb and depletion of Ba, Cs, Ni, Rb, U, Y, Co, Sc, Zn are characteristic during mineralization. The pyrophyllite ores can be discriminated from the altered-and unaltered wall-rocks by an increasing of $(La/Lu)_{cn}$ from 4.18~22.13 to 8.98~55.05. In R-mode cluster analysis, Yb-Lu-Y, La-Ce-Hf-Th-U-Zr, $TiO_2-V-Al_2O_3$, Sm-Eu, $CaO-Na_2O-MnO$, Cu-Zn-Ag, $K_2O-Rb$ are closely correlated. In the discriminant analysis of multi-element data, $P_2O_5$, As, Cr and $Fe_2O_3$, Sr are helpful to identify the ores from the unaltered-and altered wall-rocks. In the factor analysis, the factors of alteration of andesitic rocks and ore mineralization were extracted. In the change of ions per unit volume, $SiO_2$, $Al^{3+}$ and LOI are enriched and $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, $Mn^{2+}$ and $Fe^{3+}$ are depleted during the alteration processes. The Milyang and the Sungjin pyrophyllite deposits could be mineralized by hydrothermal alteration in a geochemical condition of low activity ratio of alkaline ions to hydrogen ion with reference to spatially related granitic rocks.