Authors: L. ÖZYÜZER, N. BAŞTÜRK
Abstract: The electrical properties of YBa_{2}Cu_{3}O_{7-x} screen-printed thick films on MgO(100), sapphire and alumina substrates were investigated as a function of annealing temperature. Temperature variation of resistivities were found to depend on annealing conditions. For films on Ag/sapphire and Ag/alumina substrates, the best value of calcination temperature and duration were found to be 890\pm 10^{\circ}C, 15 min. Above this temperature, resistivities increased probably due to film-substrate interaction, thus superconductor phase ratio and Tc(R=0) decreased and \Delta T(10\%, 90\%) increased. For the films prepared on bare MgO substrates, the calcination temperature interval was found to be 870-930 ^{\circ}C, which is larger than the calcination temperature interval for films on other substrates. X-ray diffraction and SEM studies indicated that the films had no preferred orientation. The best superconducting thick film with Tc(R=0)=82 K and Jc(77K)=2 A/cm^{2} was obtained on MgO.
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