We compare predictions of the mean-field theory of superconductivity for nearly antiferromagnetic and nearly ferromagnetic metals in two dimensions. The calculations are based on a parametrization of the effective interaction arising from the exchange of magnetic fluctuations. The Eliashberg equations for the transition temperature are solved including the full momentum dependence of the electron self-energy. The results show that for comparable parameters d-wave singlet pairing in nearly antiferromagnetic metals is generally much stronger than p-wave triplet pairing in nearly ferromagnetic metals in quasi-two dimensions. The relevance to the layered materials, and in particular ${\mathrm{Sr}}_2{\mathrm{RuO}}_4$ that exhibits p-wave triplet pairing, is discussed.

• Received 22 December 1998

DOI:https://doi.org/10.1103/PhysRevB.59.14598