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تسجيل مستخدم جديدAnomalous scaling behavior in a mixed-state Hall effect of a cobalt-doped BaFe2As2 epitaxial film with a high critical current density over 1 MA/cm2
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The mixed-state Hall effect was examined in a Ba(Fe1-xCox)2As2 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}xx{beta}. 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 c-axis pinning centers in the Ba(Fe1-xCox)2As2 epitaxial film and are consistent with a wider vortex liquid phase.
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