On the Sr substitution effect in the R1−xPrxBa2−ySryCu3O7 system (R=rare-earth element)

摘要: Abstract The variation of the superconducting properties with Sr concentration y in R 1− x Pr Ba 2− Cu 3 O 7 can be accounted for by taking following two factors into consideration: mutual substitution and ions on each other's sites local structural changes arising from substitution. former decreases R/Pr site, while latter modify energy a hole Cu, (through Madelung potential) hopping interaction between them bond length), thereby affecting ability to localize hole. It is argued that 2D percolation model we proposed explain 2 applicable Sr-doped system. Possible explanations are also given several problems regarding behaviour high- T c , as well insulating, cuprates, including ionic size effect N (the magnetic ordering temperature moments) related systems, e.g. Tl(Ba ) PrCu Nb(Ba 8 PrBa .