The Berezinskiy–Kosterlitz–Thouless phase transition in the Josephson medium of a two-level granular high-temperature superconductor YBa2Cu3O7–δ
T.V. Sukhareva and V.A. Finkel
National Science Center “Kharkov Institute of Physics and Technology” 1 Akademicheskaya Str., Kharkov 61108, Ukrain
Received October 19, 2018
The temperature dependences of the electrical resistivity of a granular high-temperature superconductor YBa2Cu3O7–δ ρ(Т) at different values of the transverse external magnetic field strength at 0 ≤ Нext ≤ 100 Оe are measured in the temperature range from the temperature of the appearance of resistivity Tρ = 0 to the critical temperature of the superconducting transition Tc at the transport current density from 50 to 2000 mA/cm2. The effect of the temperature and the strength of the external magnetic field, the transport current density on the kinetics of the phase transitions in both subsystems of the granular HTSC are studied. The possibility of flowing and studying the conditions for realizing the topological phase transition — the Berezinskiy–Kosterlitz–Thouless transition in the Josephson medium — is established.
PACS: 74.25.–q Properties of superconductors; PACS: 74.72.–h Cuprate superconductors.
Key words: topological phase transition, two-level granular high-temperature superconductor, YBa2Cu3O7–δ, Josephson medium, magnetic field, transport current, current–voltage characteristics.