Fabrication of superconducting oxide thin films by sol-gel method

A method of forming a superconductive thin film comprising:

• a step of preparing a solution containing an amount (a) of mols of at least one compound selected from the group A consisting of methoxide, ethoxide, propoxide, butoxide, methoxyethoxide and ethoxyethoxide of a metal selected from Y, La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu;
• an amount (b) of mols at least one compound selected from the group B consisting of methoxide, ethoxide, propoxide, butoxide, methoxyethoxide and ethoxyethoxide of a metal selected from Ba and Sr;
• an amount (c) of mols of at least one compound selected from the group C consisting of methoxide, ethoxide, propoxide, butoxide, methoxyethoxide and ethoxyethoxide of Cu;
• an amount (d) of mols for inhibiting hydrolysis of at least one compound selected from the group D consisting of monoethanolamine, diethanolamine, triethanolamine, mono-2-propanolamine, di-2-propanolamine, acetylacetone, ethylene glycol, diethylene glycol, propylene glycol and dipropylene glycol;
• and an amount (e) of liters of at least one compound selected from the group E consisting of methanol, ethanol, propanol, butanol, methoxyethanol and ethoxyethanol;
• said amounts (a)-(e) satisfying the following equations:
• 0.1.times.(a+b+c).ltoreq.d.ltoreq.3.times.(a+b+c)
• and
• 0.01.ltoreq.{(a+b+c)/e}.ltoreq.3;
• a step of forming a thin film of the solution as prepared above on a heat-resistant substrate;
• a step of drying the film thus formed;
• and
• a step of calcining said film in an oxidative atmosphere at 350.degree. to 1,100.degree. C. to make said film superconductive.