Tl-based superconductive material, a superconductive body, and a method of forming such a superconductive material or body

A method of forming a superconductor comprising:

• forming a superconductive material of the formula
• (Tl.sub.1-X1-X2 Pb.sub.X1 Bi.sub.X2).sub..alpha. (Sr.sub.1-X3 Ba.sub.X3).sub..beta. Ca.sub..gamma. Cu.sub..delta. O.sub..xi.
• where
• .ltoreq. X1.ltoreq.0.8
• 0.ltoreq.X2.ltoreq.0.5
• 0.ltoreq.X3.ltoreq.1.0
• 0.7.ltoreq..alpha..ltoreq.1.5
• 1.4.ltoreq..beta..ltoreq.3.0
• 0.7.ltoreq..gamma..ltoreq.4.5
• 1.4.ltoreq..delta..ltoreq.6
• 4.5.ltoreq..xi..ltoreq.17
• 0<X1+X2<1;
• heating said superconductive material to a temperature in the range of 950.degree. C.-1300.degree. C. for forming a liquid phase thereof;
• and
• cooling said superconductive material to a heat treatment temperature not lower than 50.degree. C. below the temperature at which the liquid phase begins to be generated, and maintaining said superconductive material at said temperature for at least 5 hours;
• and
• cooling said superconductive material to room temperature.

A method of forming a superconductor comprising the steps of:

• (a) forming a superconductive material of a formula selected from the group consisting of
• I. (Tl.sub.1-X1-X2 Pb.sub.X1 Bi.sub.X2).sub..alpha. (Sr.sub.1-X3 Ba.sub.X3).sub.2.beta. Ca.sub.2.gamma. Cu.sub.3.delta. O.sub..xi. where
• 0.ltoreq.X1.ltoreq.0.8
• 0.ltoreq.X2.ltoreq.0.5
• 0.ltoreq.X3.ltoreq.1.0
• 0. 7.ltoreq..alpha..ltoreq.1.5
• 0.7.ltoreq..beta..ltoreq.1.5
• 0.7.ltoreq..gamma..ltoreq.1.5
• 0.7.ltoreq..delta..ltoreq.1.5
• 6.0.ltoreq..xi..ltoreq.14.0
• 0<X1+X2<1,
• II. (Tl.sub.1-X1-X2 Pb.sub.X1 Bi.sub.X2).sub..alpha. (Sr.sub.1-X3 Ba.sub.X3).sub.2.beta. Ca.sub..gamma. Cu.sub.2.delta. O.sub..xi. where
• 0.ltoreq.X1.ltoreq.0.8
• 0.ltoreq.X2.ltoreq.0.5
• 0.ltoreq.X3.ltoreq.1.0
• 0.7.ltoreq..alpha..ltoreq.1.5
• 0.7.ltoreq..beta..ltoreq.1.5
• 0.7.ltoreq..gamma..ltoreq.1.5
• 0.7.ltoreq..delta..ltoreq.1.5
• 4.5.ltoreq..xi..ltoreq.11.0
• 0<X1+X2<1, and
• III. (Tl.sub.1-X1-X2 Pb.sub.X1 Bi.sub.X2).sub..alpha. (Sr.sub.1-X3 Ba.sub.X3).sub.2.beta. Ca.sub.3.gamma. Cu.sub.4.delta. O.sub..xi. where
• 0.ltoreq.X1.ltoreq.0.8
• 0.ltoreq.X2.ltoreq.0.5
• 0.ltoreq.X3.ltoreq.1.0
• 0.7.ltoreq..alpha..ltoreq.1.5
• 0.7.ltoreq..beta..ltoreq.1.5
• 0.7.ltoreq..gamma..ltoreq.1.5
• 0.7.ltoreq..delta..ltoreq.1.5
• 7.4.ltoreq..xi..ltoreq.17.0
• 0<X1+X2<1,
• (b) heating said superconductive material to a temperature in the range of 950.degree. C.-1300.degree. C. for forming a coexisting liquid phase with solid phase of said superconductive material;
• (c) cooling said superconductive material to a heat treatment temperature not lower than 50.degree. C. below the temperature at which the liquid phase begins to be generated, and maintaining said superconductive material at said temperature for at least 5 hours;
• and
• (d) cooling said superconductive material to room temperature.