R-T1-Sr-Ca-Cu-O superconductors and processes for their preparation.

A high temperature superconductor system is provided having the following formula: M-A-B-C-D-E, wherein, M is a metallic element, A is an element in Group 3B, B is an element in Group 2A, C is another element in Group 2A, D is an element in Group 1B, and E is an element in Group 6B. In one embodiment, the high temperature superconductor has the following formula: R-Tl-Sr-Ca-Cu-O (wherein R is chosen from the group consisting of La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y). Processes for making these high temperature superconductors are also disclosed