Theory of magnetic properties in the spin-triplet superconducting state of Sr2RuO4

We analyze the magnetic susceptibility in the triplet-pairing state of Sr2RuO4, assuming the chiral p-wave state d(k)similar to(k(x) + ik(y))z. The article consists of two separate parts. In the first part we use the starting from a three-band repulsive Hubbard model, and calculate the random phase approximation, NMR relaxation rate (1/T-1) as a function of temperature. In the second part we use another model containing effective triplet-pairing interaction, and discuss possible collective spin excitation in the long-wavelength region. In the both parts we take full account of the realistic multi-band electronic structure of Sr2RuO4, and use the superconducting gap determined microscopically from the electron correlation effect. (C) 2008 Elsevier Ltd. All rights reserved.