Kinetics of topological phase transitions and topological phases in the Josephson medium of granular high-temperature superconductors under the action of temperature, magnetic field and transport current

Abstract

The paper we presented is essentially the logical conclusion of a large-scale work - from developing a strategy for detecting topological BKT phase transitions in a Josephson medium of granular high-temperature superconductors to establishing the identity of topological phases arising from two fundamentally different types of external influence. The work is devoted to the study of the topological phases arising in the two-dimensional Josephson medium of granular high-temperature superconductors YBa2Cu3O7-δ during the Berezinskii-Kosterlits-Thouless phase transitions (BKT transition) under the influence of temperature, external magnetic field and transport current. The features of the behavior of magnetoresistance isotherms R(Нext)T=const and current – voltage characteristics (CVCs) E(j)T=const in the vicinity of the temperatures of the BKT phase transitions have been discovered. It has been experimentally established that granular HTSC YBa2Cu3O7-δ is a unique object for studying the influence of external actions (magnetic field, transport current) on topological phase transitions and topological phases, since in its crystal structure there are no sources of an internal magnetic field.