Resistive investigation of pseudogap state in non-stoichiometric ReBa2Cu3O7-δ (Re = Y, Ho) single crystals with account for BCS-BEC crossover

We investigate the conductivity in the basis plane of the non-stoichiometric ReBa2Cu3O7-delta (Re = Y, Ho) single crystals. The excess conductivity (Delta sigma) is described by Delta sigma similar to(1-T/T*)exp(Delta(ab)*/T) in the wide temperature range T-f < T< T*. where T* is the mean field temperature of the superconducting transition. We determined that the temperature dependence of the pseudogap (PG) is described in terms of the BCS-BEC crossover theoretical model It is observed that a reduction in the oxygen content leads to the widening of the temperature interval. in which the PG region is realized, and to the narrowing of the area of the rho(T) linear dependence in the ab-plane (C) 2009 Elsevier B V. All rights reserved.