SUPERCONDUCTIVITY IN AN OXIDE COMPOUND SYSTEM WITHOUT RARE EARTH

摘要

Described is a superconducting composition comprisinga metal oxide of the formulaT d M* e Cu f O gwherein "T" is a trivalent transition metal such as Bi,Tl, In, Sb, or mixtures thereof; "M*" is a mixture ofalkaline earth metals such as Sr and Ca, Sr and Mg, and Caand Mg in ratio of the alkaline earth metal of largeratomic radius (M L) to the alkaline earth metal of smalleratomic radius (M S) of from about 1:1 to about 3:1; "d" isa number from about 1 to about 3; "e" is a number fromabout 1 to about 6; "f" is a number from about 1 to about6; "g" is a number between from about (3d + 2e + 2f)/2 toabout (3d + 2e + 3f)/2 that provides the metal oxide withzero electrical resistance at a temperature of 77°K orhigher. Preferably "T" is bismuth; "M*" is Ca and Sr atratio of 1:2; "d" is 2; "e" is 3; "f" is 2 and "g" is anumber between about 8 to about 9 which provides saidcomposition with zero electrical resistance at atemperature of 77°K or higher.