Preferred orientation of Y-Ba-Cu-O superconducting films on polycrystalline alumina by a melt method without crucible
L H Perng; T S Chin; K C Chen; C H Lin; W Y Lin; S E Hsu; L H Perng; Dept. of Mater. Sci. & Eng., Nat. Tsing Hua Univ., Hsinchu, Taiwan; T S Chin; Dept. of Mater. Sci. & Eng., Nat. Tsing Hua Univ., Hsinchu, Taiwan; K C Chen; Dept. of Mater. Sci. & Eng., Nat. Tsing Hua Univ., Hsinchu, Taiwan; C H Lin; Dept. of Mater. Sci. & Eng., Nat. Tsing Hua Univ., Hsinchu, Taiwan; W Y Lin; Dept. of Mater. Sci. & Eng., Nat. Tsing Hua Univ., Hsinchu, Taiwan; S E Hsu; Dept. of Mater. Sci. & Eng., Nat. Tsing Hua Univ., Hsinchu, Taiwan
Журнал:
Superconductor Science and Technology
Дата:
1990-05-01
Аннотация:
The effects were studied of surface buffer layers, a sputtered gold or platinum film and/or a screen-printed Y<sub>2</sub>BaCuO<sub>5</sub> (211) layer, on the microstructure, preferred orientation and superconducting transition of YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-x</sub> (123) films, grown by a melt method without crucible on polycrystalline alumina substrates. The degree of (00L) preferred orientation (DPO) reached 89% as Pt buffer alone was used, but this was without a superconducting transition. A combined 211 layer on a sputtered metal layer resulted in films with T<sub>c-zero</sub> of above 55 K, smoother film surfaces and DPO of 44%. The growth of preferred orientation is attributed to an inhomogeneous (00L) nucleation effect during solidification. Reduced surface cracks and better connection among crystallites of the film grown on a combined buffer layer are responsible for the measurable superconducting transition.
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