YBCO Thin Film Preparation on Unbuffered Ag Substrate by Resistive Evaporation

Abstract

It is widely accepted that thin film formation of YBCO on conducting and flexible substrate is one of the keys for further development of advanced devices in the microelectronics. Various fabrication methods such as spray pyrolysis, powder-in-tube processing, dip-coating rolling-assisted biaxially textured substrate, etc., widely used for YBCO thick films (few tens of μm) production. However in this work we report for the first time on the preparation of YBCO thin film on unbuffered silver substrate using a simple conventional vacuum system equipped with only one single resistively heated evaporation source. The subsequent heat treatment was carried out under a low oxygen partial pressure and temperature that never exceeded 740° C. A thin film of Ag was first deposited on MgO substrate. A pulverized stoichiometric mixture of Y, Cu, and BaF2was then deposited on this film. The amorphous YBCO film of a 500-nm thickness was obtained after the heat treatment. The results of the film evaluation are presented and discussed.