摘要
The great practical application possibilities of high T_c superconductors make Y-123 oxides an attractive topic of research. The wide investigation on the 123 family original compositions has revealed the influence of substitution and stoichiometry on superconductivity, owing to the chemical disturbances in the nanometre scale or even at the atomic level to render a local structure change in A,B, or O sites in the perovskite framework. All 123 family members (T_c≈90 K) reported hitherto possess an orthorhombic crystal structure, with Cu-O chains and Cu-O planes being responsible for the superconducting characteristics.
