Spin-fluctuation-induced superconductivity in the copper oxides: A strong coupling calculation

We have carried out a strong coupling calculation of spin-fluctuation-induced superconductivity for ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_7$ using the experimentally determined spin excitation spectrum. We find that it is extremely important to take full account of the momentum and frequency dependence of the interaction and that while lifetime effects substantially reduce ${\mathit{T}}_{\mathit{c}}$ from its value calculated in a weak coupling approximation, it is still possible for spin fluctuations to give rise to high-temperature superconductivity.