A POSSIBLE EXPLANATION FOR THE ISOTOPE EFFECT IN HIGH-T-C AND RB3C60 SUPERCONDUCTORS

The role of pair breaking effects on the isotope effect coefficient is investigated using the generalized Abrikosov and Gorkov theory of sup erconductors. It is found that the pair breaking effects enhance the i sotope effect coefficient. This provides a plausible explanation for t he enhancement of the isotope effect coefficient as a function of impu rity concentration in yttrium-, europium-, and lanthanum-based high-T- c superconductors. It may also explain the very large value of the iso tope effect coefficient in Rb3C60 superconductors provided some intrin sic disorder is assumed.