Disappearance of superconductivity in overdoped La1.15-xPr0.85SrxCuO4 and the orthorhombic-tetragonal phase boundary.

A study of the structural and electronic phase diagram of Pr-doped La[sub 2[minus][ital x]]Sr[sub [ital x]]CuO[sub 4] is presented in order to investigate whether there is an influence of the high-temperature tetragonal-to-orthorhombic phase transition on the disappearance of superconductivity in the overdoped region. We find that Pr doping shifts the structural phase boundary to higher Sr concentrations, but that superconductivity occurs in the same Sr-concentration range as in pure'' La[sub 2[minus][ital x]]Sr[sub [ital x]]CuO[sub 4]. Thus, the disappearance of superconductivity is not related to the high-temperature structural transition, but is determined predominantly by the hole concentration in the CuO planes.