Transport properties, upper critical field and anisotropy of Ba(Fe0.75Ru0.25)2As2 single crystals

Abstract

The temperature and angle dependent resistivity of Ba(Fe0.75Ru0.25)2As2 single crystals were measured in magnetic fields up to 14 T. The temperature dependent resistivity with the magnetic field aligned parallel to c-axis and ab-planes allow us to derive the slope of dH ab c2 /dT and dH c c2 /dT near T c yielding an anisotropy ratio Γ = dH ab c2 /dT/dH c c2 /dT≈2. By scaling the curves of resistivity vs. angle measured at a fixed temperature but different magnetic fields within the framework of the anisotropic Ginzburg-Landau theory, we obtained the anisotropy in an alternative way. Again we found that the anisotropy (m c /m ab )1/2 was close to 2. This value is similar to that in Ba0.6K0.4Fe2As2 (K-doped Ba122) and Ba(Fe0.92Co0.08)2As2 (Co-doped Ba122). This suggests that the 3D warping effect of the Fermi surface in Ru-doped samples may not be stronger than that in the K-doped or Co-doped Ba122 samples, therefore the possible nodes appearing in Ru-doped samples cannot be ascribed to the 3D warping effect of the Fermi surface.