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Information × Registration Number 0221U107098, 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 26-12-2021 Organization B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine popup.description2  During the interim reporting period, detailed information was obtained on the effect of an external magnetic field up to 8 T in the orientation of the ab plane on the resistivity and fluctuation conductivity in YBa2Cu3O7-δ thin films. It was found for the first time that up to ~ 2.5 T, the magnetic field monotonically increases the resistivity, the width of the resistive transition and the coherence length along the c axis, but reduces both the critical temperature and the range of superconducting fluctuations. Fluctuation conductivity demonstrates a crossover at a characteristic temperature from 3D Aslamazov-Larkin theory near the critical temperature to 2D Maki-Thompson fluctuation theory. However, at a magnetic field of 3 T, the Maki-Thompson contribution is completely suppressed, and above the crossover temperature, the fluctuation conductivity is unexpectedly described by the 2D Aslamazov-Larkin fluctuation contribution, which indicates the formation of a 2D vortex lattice in the film under a magnetic field. At the same time, the range of superconducting fluctuations increases sharply by about 7 times, and the coherence length along the c axis shows a very unusual dependence on the critical temperature when the magnetic field increases above 3 T. Our results demonstrate the evolution of the vortex state in YBCO with increasing magnetic field. This will greatly simplify the search for methods in obtaining new superconductors with even higher critical temperatures of the superconducting transition Tc. As mentioned above, as a result of the partial implementation of the project, high-level scientific results were obtained, which were published in 1 article in a leading scientific journal. The results were presented at 4 international conferences and 2 seminars of the ILTPE of the NAS of Ukraine on the topic "Electronic properties of conducting and superconducting systems". Product Description popup.authors popup.nrat_date 2022-03-09 Close