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Information × Registration Number 0222U005251, 0121U111967 , R & D reports Title Research on the high-temperature superconductors with the purpose of developing innovative technologies popup.stage_title Head Petrenko Yevhen V., Кандидат фізико-математичних наук Registration Date 26-12-2022 Organization B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine popup.description2 At the final stage of the project, the results of a high scientific level have been obtained. We determined the temperature dependences of the upper critical fields for optimally doped YBa2Cu3O7-δ thin films below Tc and at 0 K inclusive, namely 638 and 153 T in the cases of μ0Hc2(0), H || ab and H || c, respectively. For the first time, the temperature dependences of coherence lengths along all relevant crystallographic directions were constructed, where, in particular, ξab(0) = 11,8 Å and ξc(0) = 3,0 Å. For the first time, it is shown that below ~ 40 K, both ξab(T) and ξc(T) acquire the smallest values, which practically do not change when the temperature is further reduced to zero. The effect of the 2.5 MeV electron irradiation φ on the temperature dependence of the fluctuation conductivity σ′(T) and pseudogap Δ*(T) of the optimally doped YBa2Cu3O7–δ single crystal was studied. It was established for the first time that at 4.3·1018 e/cm2, the Δ*(T) shape changes strongly and becomes the same as in optimally doped YBa2Cu3O7–δ single crystals with a very low pseudogap opening temperature T*, while no features are observed at the Tc(φ) dependence. As the irradiation dose increases up to 8.8·1018 e/cm2, the Δ*(T) form is restored and becomes the same as in well-structured YBa2Cu3O7–δ films and untwinned single crystals. The effect of annealing at room temperatures on the fluctuation conductivity and pseudogap of HoBa2Cu3O7–δ single crystals with a lack of oxygen was studied. The analysis of evolution of the Δ*(T) temperature dependence showed the possibility of the existence of spin density waves in HoBa2Cu3O7–δ in the pseudogap state. Comparison of the pseudogap parameter near Tc with Peters–Bauer theory revealed a slight increase in the density of local pairs, which accounts for the observed 9 K increase in Tc during annealing. The results were published in 4 articles in a leading scientific journal and made public in 16 reports at international conferences.  Product Description popup.authors popup.nrat_date 2022-12-26 Close