Two new high temperature superconducting homologous series of the Ba-Ca-Cu-O system have been synthesized under high pressure: Ba2Can-1CunO2n+2 [02(n -1)n] interstitially doped with Ca or Ca and Cu, and CaBa2Can-1CunO2n+3 [Ca-12(n - 1)n] with or without partial substitution of Ca between the BaO-layers by Cu. 02(n - 1)n with an I4-symmetry displays a Tc above 126 K and degrades to a lower Tc compound when exposed to air, whereas Ca-12(n - 1)n with a P4-symmetry shows a Tc only up to 107 K but is stable in air. They form a good system for studying the effects of local symmetry on superconductivity and instability.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics