YBCO 고온 초전도체 후막의 제작 및 특성 연구 = Fabrication and Characterization of High $T_c$ $YBa_2Cu_3O_7-x$ Thick Films

다국어 초록 (Multilingual Abstract)

The fabrication of Y-Ba-Cu-O films and experimental factors affecting to characteristics of films are studied in detail. Superconducting thick films are fabricated by the screen printing method. The metal-citrate precursors are obtained simply by mixing of metal nitrate with citric acid. The particle size of heat treated powders is approximately 0.3-1${\mu}{\textrm}{m}$ and the thickness of film is estimated as 30-35${\mu}{\textrm}{m}$. According to the XRD analysis, the films sintered at 870-93$0^{\circ}C$ for 10min. -6hr with P(oxygen)=1atm has the unique orthorhombic crystal symmetry indicating the 123 phae. Tc, onset is determined around 92-87。K, but it shows semiconducting behavior probably due to the oxygen deficiency in the lattice, porosity and impurities in films. Extrapolated Tc, zero is estimated as 76-50。K. For films sintered at 90$0^{\circ}C$ for 1hr, superconducting properties are observed with the room temperature resistivity of 0.025$\Omega$.cm Tc, onset at 88。K and Tc, zero at 63。K.