Abstract:
An unusual decrease in the slope of the upper critical field near $T_{c0}$ at a gradual increase in the ion implantation dose has been experimentally observed in narrow bridges formed on the base of thin HTSC YBa$_{2}$Cu$_{3}$O$_{7-x}$ films, while an increase in the defect concentration usually leads to an increase in the local slope of the phase transition line $H_{c 2}(T)$. In addition, it has been found that the temperature dependence of the upper critical field has a positive curvature near $T_{c0}$. A possible theoretical interpretation of the results is proposed. It is based on the modified Ginzburg–Landau theory with a nonuniform length of superconducting correlations.
Keywords:
thin HTSC films, resistive measurements in magnetic field, ion implantation, the Ginzburg–Landau theory with a nonuniform coherence length.
This work was supported by the Russian Foundation for Basic research (project no. 18-42-520051), the program of the Presidium of the Russian Academy of Sciences (RAS) I.1 “Fundamental problems of high-temperature superconductivity,” and also the state program of IPM RAS for 2019.
Citation:
A. V. Antonov, A. V. Ikonnikov, D. V. Masterov, A. N. Mikhaylov, S. V. Morozov, Yu. N. Nozdrin, S. A. Pavlov, A. E. Parafin, D. I. Tetelbaum, S. S. Ustavshchikov, P. A. Yunin, D. A. Savinov, “Phase diagrams of thin disordered films based on HTSC YBa$_{2}$Cu$_{3}$O$_{7-x}$ in external magnetic fields”, Fizika Tverdogo Tela, 61:9 (2019), 1573–1578; Phys. Solid State, 61:9 (2019), 1523–1528