Irradiation-induced suppression of the critical temperature in high-$T_c$ superconductors: Pair breaking versus phase fluctuations

Experiments on the irradiation-induced suppression of the temperature in high-$T_c$ superconductors are analyzed within the mean-field Abrikosov-Gor'kov-like approach. It is shown that the experimental data for YBa$_2$Cu$_3$O$_{7-\delta}$ single crystals can be quantitatively explained by the pair breaking effects under the assumption of the combined effect of potential and spin-flip scattering on the critical temperature and with account for a non-pure $d$-wave superconducting order parameter.