• Progress in Superconductivity
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• 제4권2호
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• pp.157-161
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• 2003

We have performed the electrochemical method to fabricate high temperature superconducting (TlPbBi) -(SrBa)-Ca-Cu-O films. The precursors of the superconducting sample were codeposited at a periodic pulsed-potential cycle (1 second at -4V and 1 second at -1V) on a silver substrate. The variation of structure, microstructure and element were analysed by ICP and SEM techniques. The specimens were consisted predominantly of the Tl-1212 phase and have a transition temperature of 80～87 K in low magnetic field. It was showed that each grain has the stoichiometric ratio of $T1_{0.7}$Pb_$Bi_{0.3}$ $_Sr{0.1}$ $Ba_{2.4}$ $Ca_{0.2}$ $Cu_{1.2}$ $2.5/O_{x}$ by EDX analysis.sis.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.256-259
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• 1999

새로운 구리산화물 (Pb$_{0.5}$V$_{0.5}$)Sr$_2$(Ca$_{1-x}$Pr$_x$)Cu$_2$O$_z$를 상압의 산소 분위기 열처리를 통해 합성하였다. X선 회절실험결과 x=0.5 이상일 때 Pb-1212의 단일상이 형성됨을 확인했으며, 비저항 측정결과 x=0.5 인 시편에서 T$_c$(zero)=29 K T$_c$(onset)=40 K 가 관측되었다. x=0.6 이상일 때는 초전도 특성이 관측되지 않았으며 이는 Pr의 도핑량 x 가증가할수록 a 축이 증가하고 c 축이 감소 하는 것과 밀접히 연관되는 것으로 논의되었다.

• Progress in Superconductivity
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• 제1권1호
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• pp.9-13
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• 1999

The influence of quenching temperature and annealing time on superconducting characteristics has been investigated for a $(Pb_{0.6}V_{0.4})Sr_2(Ca_{0.65}Er_{0.35})Cu_2O_z$ compound. From the resistivity measurements for samples annealed at $400^{\circ}C$ to $860^{\circ}C$ in oxygen and subsequently quenched, it is observed that $T_c$(zero) of the sample decreases with the increase of annealing temperature up to $600^{\circ}C$ and increases again beyond $700^{\circ}C$. Annealings of the sample at $860^{\circ}C$ show that $T_c$(zero) goes through a maximum of 62K with the increase of the annealing time. It is also found that $T_c$(zero) of the sample quenched from high temperature decreases when the sample is subjected to low temperature annealing below. $600^{\circ}C$ in oxygen. The experimental results indicate that the as-prepared samples contain excessive oxygen and removal of this excessive oxygen in as-prepared samples is a key factor in controlling the superconducting properties of the samples and are discussed in connection with thermal gravimetric measurements.