Production of YBa₂Cu₃O7-x Thick Films on Ag Metal Substrate Controlled by Oxygen

YBa 2 Cu 3 O 7- x superconducting thick films were formed on Ag substrate using the sol prepared from pertinent metal alkoxides. The firing conditions which cause incongruent melting and a peritectic reaction in the film were investigated. We call this the IMPERCO (incongruent melting and peritectic reaction controlled by oxygen) method. It has been found that films which undergo both reactions have excellent superconducting properties. Accordingly, the critical current density ( J c ) of 1.18×10 4 A/cm 2 at 77 K and zero magnetic field has been obtained. Roles of the boundary of the film and Ag substrate were also discussed.