Transport properties of the single-crystal La 2− xBa xCuO 4 (0≤ x≤0.11)

Abstract

We report on the temperature dependence of the in-plane electrical resistivity ρ ab and the in-plane Hall coefficient R H in various magnetic fields of the single-crystal La 2− x Ba x CuO 4 with x=0.083 and 0.11. In x=0.11, which is close to x=1/8, where the superconductivity is strongly suppressed, a clear jump in ρ ab and a drop in R H have been observed at T d2∼53 K, where the structural phase transition between the orthorhombic mid-temperature and tetragonal low-temperature phases occurs. Moreover, a sign reversal of R H has been observed below ∼25 K and the magnitude of the sign reversal increases with increasing magnetic field. In x=0.083, on the other hand, there is neither jump in ρ ab nor drop in R H at T d2, and also no sign reversal in R H at low temperatures even in magnetic fields up to 9 T. In conclusion, there is no doubt that a static stripe order of holes and spins, observed in La 1.6− x Nd 0.4Sr x CuO 4 with x∼1/8, is formed below T d2 also in La 2− x Ba x CuO 4 with x∼1/8. The R H in the stripe-ordered state has a negative value, which is consistent with the recent theory by Prelovšek et al.