Self-test of spin fluctuation pairing

The critical self-test of the spin fluctuation pairing model of high-temperature superconductivity, associated with the relative suppression of Tc by Ni and Zn impurities on Cu sites, has not been satisfied for any material for which the test has been performed, including $\rm YBa_2Cu_3O_7$. In all high-temperature superconductors that have been measured, except BCS-like ${\rm Nd}_{2-z}{\rm Ce}_z{\rm CuO}_4$, Ni and Zn suppress Tc virtually the same, which is inconsistent with cuprate plane superconductivity that results from either i) BCS-like (phonon-like) polarization pairing or ii) spin fluctuation pairing. The observed Tc-suppression in all such superconductors, including ${\rm Nd}_{2-z}{\rm Ce}_z{\rm CuO}_4$, is consistent with BCS-like charge-reservoir superconductivity.