The Identification of the First 90K Superconductor

We identified and prepared in pure form the high-temperature superconducting compound in the chemical system Y-Ba-Cu-O, an orthorhombic, oxygen efficient perovskite of stoichiometry Ba sub 2 YCu sub 3 O sub 7. Basic physical parameters were estimated. The critical current density in a bath of liquid N sub 2 at 77K exceeded 1100 A/cm sup 2. Superconductivity is the uncanny ability of some elements, metal alloys, or chemical compounds to carry electrical current without the loss of any energy: their resistivity is theoretically (and often practically) zero. Unfortunately this property generally occurs at temperatures close to absolute zero, restricting significantly its application in real-world technologies: the most familiar application is in modern MRI machines, which employ superconducting magnets.