SUPERCONDUCTIVITY OF PrBa₂Cu₃O₇ AND OF Pr_2-zCe_zSr₂Cu₂NbO₁₀

Abstract

The data for superconducting PrBa 2 Cu 3 O 7 and Pr 2-z Ce z Sr 2 Cu 2 NbO 10 indicate that the superconductivity of these compounds is normally unaffected by rare-earth-site Pr but is quenched by a Pr Ba or Pr Sr defect on the other side of an adjacent cuprate-plane. Hence the primary superconducting condensate must reside not in the cuprate planes, but in the charge-reservoir regions containing hypocharged oxygen, namely in the BaO layers or the CuO chain layers of PrBa 2 Cu 3 O 7 , and in the SrO layers of Pr 2-z Ce z Sr 2 Cu 2 NbO 10 .