Influence of electron irradiation on fluctuation conductivity and pseudogapin YBa2Cu3O7−δ single crystals

The effect of electron irradiation with the energy of 2.5 MeV on the temperaturedependences of the resistivity ρ(T) of an optimally dopedYBa2Cu3O7−δ single crystal has been studied. Thetemperature dependences of both fluctuation conductivity σ′ (T) and the pseudogap Δ*(T) on irradiation dose φhave b...

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Bibliographic Details
Published in:Low temperature physics (Woodbury, N.Y.) N.Y.), 2022-09, Vol.48 (9)
Main Authors: Omelchenko, L V, Ya, Khadzhai G, Sergeyev, D M, Vovk, R V
Format: Article
Language:English
Subjects:
Coherence length
Crossovers
Crystal structure
Electron irradiation
Radiation dosage
Single crystals
Twin boundaries
YBCO superconductors
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Summary:The effect of electron irradiation with the energy of 2.5 MeV on the temperaturedependences of the resistivity ρ(T) of an optimally dopedYBa2Cu3O7−δ single crystal has been studied. Thetemperature dependences of both fluctuation conductivity σ′ (T) and the pseudogap Δ*(T) on irradiation dose φhave been calculated within the local pair model. Here we show that with an increase in φ,the value of ρ(300 K) increases linearly, while Tc decreases linearly. Concurrently, the value of ρ(100 K)increases nonlinearly, demonstrating a feature for φ3 = 4.3⋅1018e/cm2, which is also observed in the number of other dose-dependentparameters. Regardless of the irradiation dose, in the temperature range from Tc up to T01,σ′(T) obeys the classical fluctuation theories ofAslamazov-Larkin (3D-AL) and Maki-Thompson (2D-MT), demonstrating 3D-2D crossover withincreasing temperature. The crossover temperature T0 makes it possible to determine the coherence length along thec axis, ξc(0),which increases by ∼3 times under irradiation. Furthermore, the range of superconductingfluctuations above Tc also noticeably increases.At φ1 = 0, the dependence Δ*(T) typical forsingle crystals containing pronounced twin boundaries is observed with a maximum atTpair ∼120 K and a distinct minimum at T = T01. It wasdetermined for the first time that at φ3 = 4.3⋅1018 e/cm2the shape of Δ*(T) changes strongly and becomes the same asin optimally doped YBa2Cu3O7−δ single crystals with avery low pseudogap opening temperature T* and noticeablyreduced Tpair, while at Tc(φ) there are no singularities. With an increase in theirradiation dose up to φ4 = 8.81018 e/cm2, the shape ofΔ*(T) is restored and becomes the same as inwell-structured YBa2Cu3O7−δ films and untwined singlecrystals. Moreover, in this case, Tpair andT* increase noticeably.
ISSN:1063-777X
1090-6517