MAGNON EXCHANGE MECHANISM OF SUPERCONDUCTIVITY IN A GENERALIZED KONDO-LATTICE MODEL

Magnon exchange mechanism of superconductivity is studied on the basis of the spin fermion model or a generalized Kondo lattice model, where the antiferromagnetic long range or short range order exists in the localized spins. We obtain the effective interaction and the gap equation taking into account the two magnon exchange interaction. The gap equation is solved just below the transition temperature in the quasi-two-dimensional cases. As a result, it is found that the triplet pairing superconductivity is favored for dilute fermion densities, while the singlet pairing is favored for high densities. The transition temperature is found to be very low for realistic parameters. The possibility that the superconductivity by the magnon exchange interaction is observed experimentally is discussed.