한국초전도학회:학술대회논문집

The Korean Superconductivity Society (한국초전도학회)
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Effects of post-annealing temperature of CeO$_2$ buffer layers on the surface morphology, structures and microwave properties of YBa$_2$Cu$_3$O$_{7-{\delta}}$ films on sapphire

  • Yang, W.I. (Department of Physics and Center for Advanced Materials and Devices) ;
  • Lee, J.H. (Department of Physics and Center for Advanced Materials and Devices) ;
  • Ryu, J.S. (Department of Physics and Center for Advanced Materials and Devices) ;
  • Ko, Y.B. (Department of Physics and Center for Advanced Materials and Devices) ;
  • Chung, Y.S. (Department of Physics and Center for Advanced Materials and Devices) ;
  • Hur, Jung (Department of Electronic Engineering Konkuk University) ;
  • Lee, Sang-Young (Department of Physics and Center for Advanced Materials and Devices)
  • Published : 2000.08.16
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Abstract

Effects of the post-annealing temperature of CeO$_2$ buffer layers on the properties of YBCO films on CeO$_2$-buffered sapphire were investigated. 45 nm-thick CeO$_2$ buffer layer was prepared in-situ on r-cut sapphire using an on-axis rf magnetron sputtering method, which was later post-annealed at temperatures between 950$^{\circ}$C and 1100$^{\circ}$C in an oxygen-flowing environment. YBCO films were prepared on CeO$_2$-buffered sapphire (CbS), for which the surface morphology, crystal structures and electrical properties of the YBCO films were studied. YBCO films on post-annealed CbS appeared to have better properties than those on as-grown CbS with regard to the morphological, structural and electrical properties when the YBCO films were prepared on CeO$_2$ buffer layer post-annealed at temperatures of 1000 - 1050$^{\circ}$C. A TE$_{011}$ mode rutileloaded cylindrical cavity resonators was fabricated with the YBCO films placed as the endplates, for which the unloaded Q of the resonator was measured. It turned out that the resonator with the endplates prepared from the YBCO films on postannealed CbS at 1000 $^{\circ}$C showed the highest unloaded Q with the value more than 8 ${\times}$ 10$^5$ at 30 K and 8.6 CHz, revealing that the YBCO films on post-annealed CbS at 1000$^{\circ}$C the temperature could be the lowest among the YBCO films on post-annealed CbS.

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