The interrelationship of Cu effective charge and superconductivity in the T´-type Gd_1.85-xPr_xCe_0.15CuO_ysystem

Abstract

The lattice oxygen content (y ) is measured and the effective charge (n ) on Cu is calculated for the T´-type Gd1.85-x Prx Ce0.15 CuOy 0.0 x 1.85 compounds. It is found that the superconductive response (Tc onset) of the samples is related to n . Whenever n 1.87 (±0.01), the compounds are superconducting. The optimum Tc is seen for n ~1.79 which is in good agreement with the values of n (1.77 n 1.84) calculated from the reported y in different optimum Tc T´-cuprates. This brings out a universality in the interrelationship between n and Tc .