PREPARATION OF BI2SR2CACU2OY FILMS ON ALUMINA SUBSTRATES WITH A CUAL2O4 BUFFER LAYER

초록

High-T(c) Bi2Sr2CaCu2Oy films have been prepared using the surface diffusion process, with the screen printing of Bi2O3, SrCO3, and CaCO3 (Bi:Sr:Ca = 2:2:2) mixed powders on Cu-deposited alumina substrates. Through the heating at temperatures above 400-degrees-C, CuAl2O4 buffer layers were formed via an interaction between the Cu layer and alumina. The Bi2Sr2CaCu2Oy films, heat treated at 860-degrees-C for 30 min in air, have a zero resistance at 72 K. The x-ray diffraction, scanning electron microscope, and energy dispersive x-ray analysis studies show that the Bi2Sr2Ca1Cu2Oy films are strongly c-axis oriented along the direction normal to the alumina substrate, and the CuAl2O4 buffer layer acted as a barrier to suppress the interdiffusion of Al ions into the superconducting films.

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