Fermionic Heisenberg glasses with BCS pairing interaction

We have analyzed a fermionic infinite-ranged quantum Heisenberg spin glass with BCS coupling in real space in the presence of a magnetic field. It has been possible to locate the transition line between the normal-paramagneti c phase and the phase where there is a long-range order corresponding to pa ir formation in sites. The nature of the transition line is also investigat ed. This transition ends at T-f, the transition temperature between NP and spin glass phase where the static approximation and replica symmetry ansatz are reliable. (C) 2001 Elsevier Science B.V. All rights reserved.