The interrelationship of cu effective charge and superconductivity in the t '-type gd1.85-xprxce0.15cuoy system

Abstract

The lattice oxygen content (y) is measured and the effective charge (n) on Cu is calculated for the T'-type Gd1.85-xPrxCe0.15CuOy 0.0 less than or equal to x less than or equal to 1.85 compounds. It is found that the superconductive response (T-c onset) of the samples is related to n. Whenever n less than or equal to 1.87 (+/-0.01), the compounds are superconducting. The optimum T-c is seen for n similar to 1.79 which is in good agreement with the values of n (1.77 less than or equal to n less than or equal to 1.84) calculated from the reported y in different optimum TcT'-cuprates. This brings out a universality in the interrelationship between n and T-c.