Critical magnetic fields of anomalous superconductors

The thermodynamic H-c, lower H-c1 and upper H-c2 critical magnetic fields and their behaviours are investigated beyond the standard Fermi- liquid (i.e. BCS) approximation within the novel Fermi-Bose- liquid model of superconductivity It is shown that a simple relationship between H-c (H-c1 and H-c2 also) and the order parameter Delta(B) of delete attracting 3d- boson-like carriers (e.g., cooperons and bipolarons) and specific features of Delta(B) are responsible for all observed anomalies (i.e. crossover or kink-like and upward increasing behaviours) of H-c, H-c1 and H-c2 near some characteristic temperature T = T-B* < T-c and wide-spreading positive curvature and root-like temperature dependences near T-c in many superconductors. (C) 1997 Academic Press Limited.