Thermodynamic characteristics of the one-dimensional attractive Hubbard model are calculated by means of the generalized self-consistent field (GSCF) approach for a wide range of interaction strength U⩽0, in the presence of external magnetic field h⩾0, temperature T⩾0 and electron concentration 0⩽n⩽1. The GSCF theory shows a sharp transition driven by h>0 and T from the uniform superconducting state into a spatially inhomogeneous state in which the order parameter Full-size image (<1 K) has wave vector (Full-size image (<1 K)). The concentration of double occupied sites and the bound electron pairs with opposite spins npair are calculated and we found a simple relationship between the order parameters Full-size image (<1 K) and average spin s, valid for the arbitrary U, all n and h.
