Evolution of fluctuation conductivity of Y1Ba2Cu3O7-Δ single crystals under the influence of medium doses of electron irradiation and doping with praseodymium

Abstract

The influence of medium doses (from 1019 cm–2 to 1020 cm–2) of irradiation with fast electrons and changes in the concentration of praseodymium in the interval 0.0 ≤ z ≤ 0.5 on the excess conductivity of optimally oxygen-doped Y1Ba2Cu3O7-δ single crystals was studied. It is shown that electron irradiation and an increase in the degree of doping with praseodymium leads to a significant expansion of the temperature interval of the existence of excess conductivity, thereby narrowing the region of the linear dependence of r(Т) in the ab-plane. It was established that at doses 0 ≤ D ≤ 6.5´1019 cm–2 the value of the value of the transverse coherence length ξс(0) increases with an increase in D approximately 3 times and more than four times as the praseodymium content in the sample increases to z ≈ 0.42. At the same time, in both cases, the 2D-3D crossover point is shifted by temperature. In contrast to the case of irradiation with small doses (D ≤ 1019 cm–2) and doping with praseodymium up to concentrations z ≤ 0.39, irradiation with medium doses and doping with praseodymium at higher concentrations leads to a non-monotonic dependence of the transverse coherence length xс(0) with characteristic maxima at D ~ (7-8)´1019 cm–2 and z ≈ 0.42, which may be related to the general suppression of superconducting characteristics.