Anomalous scaling behavior in a mixed-state Hall effect of a cobalt-doped BaFe2As2 epitaxial film with a high critical current density over 1 MA/cm(2)

Article

关键词: FLUX-PINNING MECHANISMS;    II SUPERCONDUCTORS;    GRAIN-BOUNDARIES;    VORTEX MOTION;    THIN-FILMS;    RESISTIVITY;    FLOW;   

DOI  :  10.1103/PhysRevB.87.064504

来源: SCIE

【 摘 要 】

The mixed-state Hall effect was examined in a Ba(Fe1-xCox)(2)As-2 epitaxial film with a high critical current density. The transverse resistivity rho(xy) and the longitudinal resistivity rho(xx) follow power law scaling rho(xy) = A rho(beta)(xx). In the temperature sweep with a fixed field (T sweep), all of the beta values are independent of magnetic field up to 9 T, and are lower than 2.0 (around 1.8). In contrast, the beta values in the magnetic-field sweep with a fixed temperature (H sweep) change from 1.8 to 2.0 as the temperature increases from 13 to 16 K even in the T/H region that overlaps with the T sweep measurements. These results indicate that the vortices introduced at low temperatures are trapped by strong pinning centers, but a portion of the vortices introduced at high temperatures are not strongly trapped by the pinning centers. The sign of rho(xy) is negative, and a sign reversal is not detected. These distinct scaling behaviors, which sharply contrast cuprates and MgB2, are explained by high-density pinning centers in the Ba(Fe1-xCox)(2)As-2 epitaxial film and are consistent with a wider vortex liquid phase. DOI: 10.1103/PhysRevB.87.064504

【 授权许可】

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