STRUCTURE AND SUPERCONDUCTIVITY IN LA1.15-XPR0.85SRXCUO4

A phase diagram of Pr-doped La2-xSrxCuO4 including structural and supe rconducting properties is presented. We find that Pr-doping shifts the phase boundary of the high temperature tetragonal to orthorhombic pha se transition to higher Sr-concentrations without inducing the low tem perature structural phase transition as other RE do. As superconductiv ity occurs in the same Sr-concentration range as in ''pure'' La2-xSrxC uO4 (LSCO), the disappearance of supercondctivity is not related to th e high temperature structural transition, but is determined predominan tly by the hole-concentration in the CuO-planes. The decrease of T-c o f approximate to 5-10 K in the Pr-doped samples with respect to the un doped ones can mainly be attributed to the increase of the octahedra t ilting angle.