A link between critical transition temperature and the structure of superconducting YBa2Cu3O7-δ

A correlation has been found between the Cu3+-ion/oxygen deficiency positions in the CuO2 plane and the critical transition temperature Tc in the high temperature superconducting (HTSC) material YBa2Cu3O7-δ. Two modes are responsible for the two transition temperatures at 93 and 57 K given by δ deficiency values of 0.04 and 0.45, respectively.