Influence of Uniform Compression on the Temperature Dependence of the Pseudogap of Medium-Praseodymium-Doped Y_1−x Pr_x Ba₂ Cu₃ O _7−δ Single Crystals

The effect of high pressure on the conductivity in the basal plane of HTSC single crystals of Y_0.77Pr_0.23Ba₂Cu₃O_7−δ is investigated. It has been established that the excess conductivity, Δσ(T), of these single crystals in a wide temperature range T_f < T < T* can be described by an exponential temperature dependence. The description of the excess conductivity using the relation Δσ ~ (1 − T/T*)exp(Δ*_ab/T) can be interpreted in terms of the mean-field theory, where T* is represented as the temperature pseudogap opening, and the temperature dependence of the pseudogap (PG) is satisfactorily described in the framework of the BCS-BEC crossover theory. An increase in the applied pressure leads to the effect of narrowing the temperature interval for the realization of the PG-regime, thereby expanding the region of the linear dependence ρ(T) in the ab-plane.