Fizika Nizkikh Temperatur: Volume 46, Number 11 (November 2020), p. 1253-1260 ( to contents , go back )
The effect of the chaotic pinning potential on intrinsic pinning in YBa2Cu3O7–δ single crystals
N. R. Vovk1,2, R. V. Vovk1,3, G. Ya. Khadzhai1, V. I. Biletskyi1, A. V. Samoylov1,3, A.V. Solovyov1,4, and A. V. Matsepulin1
1V. N. Karazin Kharkiv National University, Kharkiv 61022, Ukraine
2IFIMUP, Departamento de Fisica, Universidade de Porto, Porto 4169-007, Portugal
3Ukrainian State Academy of Railway Transport, Kharkiv 61050, Ukraine
4B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine Kharkiv 61103, Ukraine
Received May 12, 2020, published online September 21, 2020
We study the temperature dependence of the in-plane magneto-resistance ρab(T) in the untwined YBa2Cu3O7–δ single crystals after irradiation by fast electrons (energy 0.5–2.5 MeV, dose 1018 cm−2), also with a small oxygen hypostoichiometry at different angles between the external magnetic field 15 kOe and the ab-planes α. We found that at high temperatures in the pseudogap region external magnetic field does not affect the ρab(T), but itbroadens transitional region Tc – Tc0 from 0.3 K at zero field and α = 0 to approximately 6 K at α = 90° in the field. In the case of an unirradiated sample, ρab(T)display a 3D to 2D dimensional crossover when temperature decreases from Tc to Tc0 and scaling near the Tc0 which we relate to the flux-flow and vortex-lattice melting. The reasons for the appearance of low-temperature “tails” (paracoherent transitions) on resistive transitions corresponding to different phase regimes of the vortex matter are discussed.
Key words: YBaCuO single crystals, magnetoresistance, 2D–3D dimensional crossover, vortex matter, irradiation, oxygen deficiency, intrinsic pinning.