Normal state properties of quasi-2D superconductors due to spin fluctuations

Spin fluctuation effects are studied in quasi-2D superconductors.. such as high critical temperature superconductors and organic 2D BEDT-TTF superconductors (with T-c smaller than 13 K). We discuss the important similarities and differences between these two systems. We show that, due to nesting properties of the Fermi surface, the magnetic and the transport properties are different from the behaviours we should observe in usual metal, because of strong magnetic fluctuation effect. We distinguish different regions in the normal state with different dependences as a function of temperature for several properties, such as the resistivity, NMR relaxation rate and spin susceptibility. We show that the pseudogap region is strongly related to the existence of a pseudogap in the density of states at the Fermi level. (C) 2004 Elsevier B.V. All rights reserved.