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YBa2Cu3O7-x films with Ba2Y(Nb,Ta)O6 nanoinclusions for high field applicationsстатья
- Авторы: Celentano Giuseppe, Rizzo Francesco, Augieri Andrea, Mancini Antonella, Pinto Valentina, Rufoloni Alessandro, Vannozzi Angelo, MacManus-Driscoll Judith L., Patrick Frederick Feighan John, Kursumovic A., Meledin Alexander, Mayer Joachim, Tendeloo Gustaaf Van
- Журнал: Superconductor Science and Technology
- Год издания: 2020
- Издательство: IOP Publishing
- Местоположение издательства: [Bristol, UK], England
- DOI: 10.1088/1361-6668/ab6ee5
- Аннотация: Structural and transport properties of YBa2Cu3O7-x films grown by pulsed laser deposition with mixed 2.5 mol.% Ba2YTaO6 (BYTO) and 2.5 mol.% Ba2YNbO6 (BYNO) double-perovskite secondary phases are investigated in an extended film growth rate, R = 0.02 - 1.8 nm/s. The effect of R on the film microstructure analyzed by TEM techniques shows an evolution from sparse and straight to denser, thinner and splayed continuous columns, with mixed BYNO+BYTO (BYNTO) composition, as R increases from 0.02 nm/s to 1.2 nm/s. This microstructure results in very efficient flux pinning at 77 K leading to a remarkable improvement of the Jc behaviour, with the maximum of the pinning force density Fp(Max) = 13.5 GN/m3 and the irreversibility field in excess of 11 T. In this range, the magnetic field values at which the Fp, is maximized varies from 1 T to 5 T being related to the BYNTO columnar density. The film deposited with R = 0.3 nm/s exhibits the best performances over the whole temperature and magnetic field ranges achieving Fp(Max) = 900 GN/m3 at 10 K and 12 T. At higher rates, R > 1.2 nm/s, BYNTO columns show a meandering nature and are prone to form short nanorods. In addition, in the YBCO film matrix a more disordered structure with a high density of short stacking faults is observed. From the analysis of the Fp(H, T) curves it emerges that in films deposited at the high R limit, the vortex pinning is no longer dominated by BYNTO columnar defects, but by a new mechanism showing the typical temperature scaling law. Even though this microstructure produces a limited improvement at 77 K, it exhibits a strong Jc improvement at lower temperature with Fp = 700 GN/m3 at 10 K, 12 T and 900 GN/m3 at 4.2 K, 18 T.
- Добавил в систему: Меледин Александр Александрович