• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.10
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• pp.731-735
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• 2013

YBCO thin films on $SiO_2$/Si substrate were fabricated by spin-coaing of an alkoxide-derived precursor and heat treatment. The structural and electrical properties of the YBCO films were investigated as functions of annealing temperature at $600{\sim}800^{\circ}C$. Although YBCO single phase was not synthesized, dense films of YBCO matrix phase and minor second phases have been successfully fabricated at the annealing temperatures of $650{\sim}800^{\circ}C$. Thickness and temperature coefficient of resistance (TCR) of YBCO thin films with annealing temperature of $750^{\circ}C$ were 0.31 ${\mu}m$ and $-2.92%/^{\circ}C$, respectively.

• Journal of the Korean Ceramic Society
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• v.27 no.3
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• pp.299-310
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• 1990

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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.9
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• pp.1296-1299
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• 2012

$YBa_2Cu_3O_{7-x}$ thin films were fabricated by the spin-coating method on $SiO_2$/Si substrate using an alkoxide-based sol-gel method. The structural and electrical properties were investigated for various 1st annealing temperature. Due to the formation of the polycrystalline single phase, synthesis temperature was observed at around $720^{\circ}C-800^{\circ}C$. $YBa_2Cu_3O_{7-x}$ thin films with the 1st annealing temperature of $450^{\circ}C{\sim}500^{\circ}C$ showed the single XRD patterns without the second phase, such as $YBa_2Cu_4O_8$. The thickness of films was approximately $0.23{\mu}m{\sim}0.27{\mu}m$. Aerage grain size, resistance and temperature coefficient of resistance (TCR) of $YBa_2Cu_3O_{7-x}$ thin films with the 1st annealing temperature of $500^{\circ}C$ were $0.27{\mu}m$, $59.7M{\Omega}$ and -3.7 %/K, respecvitely.