• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.341-344
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• 2004

The superconducting properties of $YBa_2Cu_3O_x$ with different content impurities of PbO and $BaPbO_3$ were studied. When the PbO was used as an additive in $YBa_2Cu_3O_x$, although the melting point could be reduced, the superconductivity became poor. From the XRD pattern of the sintered mixture of $YBa_2Cu_3O_x$ and PbO it was known that there is a reaction between $YBa_2Cu_3O_x$ and PbO, and the product is $BaPbO_3$. In the process of the reaction the superconducting phase of $YBa_2Cu_3O_x$ was decreased and $BaPbO_3$ would be the main phase in the sample. Therefore, $BaPbO_3$ was chosen as the impurity additive for the comparative study. The single phase of $BaPbO_3$ was synthesized by the simple way from both mixtures of $BaCO_3$ and PbO, $BaCO_3$ and $PbO_2$. Different contents of $BaPbO_3$ (10%, 20%, 30%) were added in the $YBa_2Cu_3O_x$. By the Phase analysis in the XRD patterns it was proved that there was no reaction between $YBa_2Cu_3O_x$ and $BaPbO_3$. When $BaPbO_3$ was used as impurity in $YBa_2Cu_3O_x$ the superconductivity was much better than PbO as an impurity additive in $YBa_2Cu_3O_x$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.3
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• pp.269-274
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• 2002

(Sm/Y)-Ba-Cu-O system high Tc composite superconductors with/without $CeO_2$ additive were directionally grown by zone-melting process, haying large temperature gradient, In air atmosphere. Cylindrical green rods of $({Sm/y})_{1.8}Ba_{2.4}Cu_{3.4}O_x$ [(Sm/Y)1.8] composite oxides by cold isostatic pressing(CIP) method using rubber mold were fabricated. The microstructure and superconducting properties were investigated by XRD, SEM, TEM and SQUID magnetometer. The size of nonsuperconducting $({Sm/y})_2BaCuO_5$ inclusions of the melt-textured (Sm/Y)1.8 sample with CeO$_2$ additive were remarkably reduced and uniformly distributed within the superconducting (Sm/Y)1.8 matrix. Both samples, with/without $CeO_2$ additive, showed an onset Tc $\geq$ 90 K and sharp superconducting transition. The critical current density Jc value of the $CeO_2$ addictive were $1{\times}10^5A/\textrm{cm}^2$ in 77 K, 0 Tesla.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.2
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• pp.110-113
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• 2016

(YNdSm)-Ba-Cu-O system high Tc composite superconductors were directionally grown by zone melting process, having large temperature gradient, in air atmosphere. Cylindrical green rods of $(YNdSm)_{1.8}Ba_{2.4}Cu_{3.4}O_x$ [(YNS)1.8]composite oxides by CIP (cold isostatic pressing) method using rubber mold were fabricated. The microstructure and superconducting properties were investigated by XRD, TEM and SQUID magnetometer. The size of nonsuperconducting $(YNdSm)_2BaCuO_5$ inclusions of the melt-textured (YNS)1.8 sample with $CeO_2$ additive were remarkably reduced and uniformly distributed within the superconducting (YNS)1.8 matrix. (YNS)1.8 samples, with / without $CeO_2$ additive, showed an onset $T_c{\geq}90K$ and sharp superconducting transition. The critical current density $J_c$ value of the (YNdSm)1.8 superconductor with $CeO_2$ additive were 840 A, $1.2{\times}104A/cm^2$ in 77 K, 0 Tesla by direct current transport method.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.107-109
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• 2003

This paper was to measure the structure, piezoelectric properties of $0.03Pb(Mg_{0.5}W_{0.5})O_3$ - $0.12Pb(Sb_{0.5}Nb_{0.5})O_3$ - $0.85Pb(Zr_{0.52}Ti_{0.48})O_3$ + $0.5[wt%]MnO_2$ ceramics dropped with additive CuO after manufacturing the specimens with a general method. It is shown that X-ray diffraction pattern variation of lines (211) have tendency to move minutely by addition of additive CuO. According to dropping with Cu, the dielectric constant at 20[$^{\circ}C$] reduced to CuO 3.0[wt%]. In case of sintering at 1050[$^{\circ}C$], dielectric constant was maximum value 623.59 at CuO 1.0[wt%]. Dielectric loss was maximum value 2.7[%] at Cu 2.0[wt%] in case of sintering at 1050[$^{\circ}C$].

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.6
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• pp.241-248
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• 2003

$Bi_{1.84}Pb_{0.34}Sr_{1.91}Ca_{2.03}Cu_{3.06}O_{10+\delta}$ high $T_{c}$ superconductors containing Ag as an additive were fabricated by a solid-state reaction method. The superconducting properties, such as the structural characteristics, the critical temperatures, the grain size and the image of mapping on the surface were investigated. Samples with Ag and Au of 50 wt% each were sintered at various temperature(820~$850^{\circ}C$). The structural characteristics, the microstructure of surface and the critical temperature with respect to the each samples were analyzed by XRD and SEM, EDS and four-prove methode respectively. The critical temperature showed the result which the Ag additive samples are higher than Au additive samples. The microstructure of the surface showed the tendency which the Ag additive samples become more minuteness than Au additive samples.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.556-560
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• 1995

The absorption properties of Cu-Zn ferrite/rubber composite microwave absorbers with PZT(Lead Zirconate Titanate) additive were evaluated. The composite specimens have prepared by molding and curing the mixture of matrix rubber and Cu-Zn ferrite powders which are synthesized by the coprecipitation method using Fe Cl/sub 3/ .center dot. 6H/sub 2/O, CuCl/sub 2/ .center dot. 2H/sub 2/O and Zn Cl/sub 2/ as a starting raw materials. PZT is used as another filler particles to adjust the material constants of Cu-Zn ferrite/rubber composite specimens. We have found that the material constants of specimens could be controlled by various PZT mixing ratio. On the Cu-Zn ferrite/rubber composite specimens with PZT 10[wt%] additive, the reflection losses were larger than 30[dB] in the frequency range from 2.72 to 4.4[GHz]' by adjusing the thickness.

• Journal of the Korean Magnetics Society
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• v.16 no.4
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• pp.201-205
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• 2006

The electromagnetic properties and microstructure of the basic composition of $(Ni_{0.2}Cu_{0.2}ZnO_{0.2})_{1.02}(Fe_{2}O_{3})_{0.98}$ were invested, changing the amount of the additives $Bi_2O_3$ and $ZrO_2$ and sintering temperature. The spinel structure of specimen was confirmed by the analysis of XRD patterns. Grain size and its density are increased by increasing the additive and the sintering temperature.However, the permeability increased with decreasing additive. It was also found that $Bi_2O_3$ had more effect on the increase of grain size and permeability rather than $ZrO_2$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.5
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• pp.188-192
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• 2005

High $T_c(Y_{0.5}Nd_{0.25}Sm_{0.25})Ba_2Cu_3O_y[(YNS)-123]$ superconductors with/without $CeO_2$ additive were systematically investigated by the zone melt growth process in air. Cylindrical green rods of (YNS)-123 oxides were fabricated by cold isostatic pressing (CIP) method using rubber mould. A sample prepared by this method showed well-textured microstructure, and $(Y_{0.5}Nd_{0.25}Sm_{0.25})_2BaCuO_5[(YNS)211]$ nonsuperconducting inclusions were uniformly dispersed in large $(Y_{0.5}Nd_{0.25}Sm_{0.25})Ba_2Cu_3O_y$[(YNS)123] superconducting matrix. In this study, optimum melting temperature and growth rate were $1100^{\circ}C$ and 3 mm/hr, respectively. The directionally melt-textured (YNS)-123 sample with $CeO_2$ additive showed an onset critical temperature $(T_c)\;T_c{\geq}93K$ and sharp superconducting transition.

• Journal of the Korean Electrochemical Society
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• v.18 no.1
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• pp.7-16
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• 2015

Effects of chemical composition ($Cu^{2+}$, $K_4P_2O_7$ and additive concentrations) of baths on properties of Cu thin films electrodeposited from pyrophosphate copper bath were investigated. Current efficiency was increased to be near 100% with increasing $Cu^{2+}$ concentrations from 0.02 to 0.3M. Decrease of current efficiency was observed in the range of 1.5~1.8M $K_4P_2O_7$ concentration, but current efficiency of about 100% was measured in the ranges of both 0.9~1.3M and 2.1~2.4M. The change of additive concentration did not influenced current efficiency. Residual stress of electrodeposited Cu thin films was measured to be about 20 MPa below 0.15 M $Cu^{2+}$ concentration and increased with the increase of it to 0.25 M. Maximum residual stress of 120MPa was observed at 0.25M $Cu^{2+}$ concentration. On the other hand, residual stress decreased from 80 to near 0 MPa as $K_4P_2O_7$ concentration varied from 0.9 to 2.4M and but The change of additive concentration did not affected on residual stress. $Cu^{2+}$ and $K_4P_2O_7$ concentrations significantly affect on surface morphology of electrodeposited Cu thin films, but additive concentration slightly affected. From XRD analysis, the microstructures of electrodeposited Cu thin film was affected from the changes of $Cu^{2+}$ and $K_4P_2O_7$ concentrations, but not from that of additive concentration. Strong preferred orientation of (111) peak was observed with increasing $Cu^{2+}$ and $K_4P_2O_7$ concentrations.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.4
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• pp.308-313
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• 2002

Samples with the norminal composition, $Bi_{2-x}Au_xSr_2CaCu_2O_{8+\delta}$ (x = 0, 0.05. 0.1, 0.15) were prepared by the solid-state reaction method. The superconducting properties, x-ray powder diffraction patterns, critical temperature and microstructure of surface were measured the samples. x-ray patterns show the single phase(2212) nature of the samples. But, the peaks of 2201 at $2\theta=30^{\circ}$ and Au peak at $2\theta=38.31^{\circ}$ are observed in the Au additive samples. The grain sire are enlarged with the increase of x. As the result of enlargement the grain size, the onset and offset critical temperature($T_c^{on}$,$T_c^{zero}$) increased with increase of x.