Temperature dependence of the pseudogap in Y_(1-z)Pr_zBa_2Cu_3O_(7-δ) single crystals

摘要

We investigate the conductivity in the basis plane of Y_(1-z)Pr_zBa_2Cu_3O_(7-δ) and YBa_2Cu_3O_(7-δ) single crystals. The excess conductivity, △σ, is described by △σ ~ (1 - T/T*)exp(△_(ab)*/T) in a wide temperature range T_f < T < T*, where T* is the mean field temperature of the superconducting transition. We determine 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 praseodymium content results to the widening of the temperature interval that the PG region is realized and a narrowing of the area of existence of the linear dependence of the resistivity, p(T), in the ab plane.