Longitudinal and Hall resistivities, scaling behavior, and magnetizations are examined to study the effect of flux pinning in Ba(Fe1-xCo x)2As2 (BFCA) single crystals with x=0.08 and 0.01. Larger values of activation energy, critical current density, and pinning force are obtained in BFCA with x=0.10, indicating relatively strong pinning. The sign reversal of Hall resistivities is clearly observed in BFCA with x=0.10. The correlation between longitudinal and Hall resistivities shows the scaling behavior of ρxy(ρxx)β with exponents β=3.0-3.4 and 2.0±0.2 for BFCA crystals with x=0.08 and 0.10, respectively. Furthermore, the normal-state Hall angle is also observed to follow cotθH=ΛT2+C in BFCA crystals, and is explained by the Anderson theory. The relatively large c/Λ value for BFCA with x=0.10 also implies a larger contribution of impurity scattering due to more Co atoms, which may cause stronger pinning of flux lines. The results are analyzed and coincide with theory, including the pinning-induced backflow effect and plastic flow mechanism in vortex dynamics.
|Physical Review B - Condensed Matter and Materials Physics
|Published - 2011 Apr 7
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics