Superconductivity up to 126 Kelvin in Interstitially Doped Ba₂Ca_<i>n</i>_-₁Cu_<i>n</i>O_<i>x</i>[02(<i>n</i>-1)<i>n</i>-Ba]

Abstract

A new high-temperature superconducting compound system, Ba 2 Ca n – 1 Cu n O x [02( n –1) n –Ba] interstitially doped with calcium or (Ca,Cu) has been identified to exhibit a transition temperature up to 126 kelvin, the highest for a superconductor without a volatile toxic element. 02( n –1) n –Ba has body-centered tetragonal symmetry and an unusual charge-reservoir block. The compounds offer interesting opportunities for high-temperature superconductivity science and technology.