Process for preparing a superconducting thin film

A process for preparing a superconducting thin film on a substrate, consisting essentially of the steps of:

• (a) forming a target of a particular material comprising oxygen,, copper, lanthanum, and strontium or barium;
• (b) sputtering said particular material from said target onto a substrate selected from the group consisting of single crystals of magnesia, strontium, titanate, beryllia, alumina, silicon and yttrium stabilized zirconia to form a superconductive thin film on said substrate, said sputtering step including the steps of
• (i) supplying additional oxygen from an oxygen supply to said thin film during said sputtering step, said additional oxygen being in addition to said oxygen available from said particular material and being in an effective amount to form said thin film as a compound oxide which is superconductive, and
• (ii) controlling heating of said substrate during said sputtering step by applying heat to said substrate from an adjustable heat source distinct from said substrate, distinct from said target and distinct from said oxygen supply to control said substrate at an effective temperature of about 900.degree. C. to cause said compound oxide to be superconductive,
• said sputtering step producing said compound oxide having a composition
• (La.sub.1-x M.sub.x M.sub.x).sub.2 CuO.sub.4-y
• wherein,
• M is Sr or Ba,
• <
• x<1,
• 0.ltoreq.y<4,
• said compound oxide having a crystal structure similar to that of K.sub.2 NiF.sub.4 -type oxides;
• and
• (c) heat treating said compound oxide, after said sputtering step, at an effective temperature and for an effective duration to cause said compound to become superconductive at a T.sub.c of 25.degree.-38.degree. K.

A process for preparing a superconducting thin film on a substrate, consisting essentially of the steps of:

• (a) forming a target of a particular material comprising oxygen, copper, lanthanum, and one of strontium or barium, said target being formed of compounds selected from the group consisting of oxides, carbonates, nitrates and sulfates of copper, lanthanum, and one of strontium or barium;
• (b) sputtering said particular material from said target onto a substrate to form a superconductive thin film on said substrate, said sputtering step including the steps of
• (i) supplying additional oxygen from an oxygen supply to said thin film during said sputtering step, said additional oxygen being in addition to said oxygen available from said particular material and being in an effective amount to form said thin film as a compound oxide which is superconductive, and
• (ii) controlling heating of said substrate during said sputtering step by applying heat to said substrate from an adjustable heat source distinct from said substrate, distinct from said target and distinct from said oxygen supply to control said substrate at an effective temperature of about 900.degree. C. to cause said compound oxide to be superconductive,
• said sputtering step producing said compound oxide having a composition
• (La.sub.1-x M.sub.x).sub.2 CuO.sub.4-y
• wherein,
• M is Sr or Ba,
• 0<x<1,
• 0.ltoreq.y<4,
• said compound oxide having a crystal structure similar to that of K.sub.2 NiF.sub.4 -type oxides;
• and
• (c) heat treating said compound oxide, after said sputtering step, at a temperature of 600.degree. to 1200.degree. C. for a period of time effective to cause said compound to become superconductive at a T.sub.c of 25.degree.-38.degree. K.