Magnetic-field effects on the in-plane electrical resistivity in single-crystal La _2-xBa _xCuO ₄ and La _1.6-xNd _0.4Sr _xCuO ₄ around x=1/8: Implication for the field-induced stripe order

Temperature dependence of the in-plane electrical resistivity, ρ _ab, in various magnetic fields has been measured in the single-crystal La _2-xBa _xCuO ₄ with x=0.08, 0.10, 0.11 and La _1.6-xNd _0.4Sr _xCuO ₄ with x=0.12. It has been found that the superconducting transition curve shows a so-called fan-shape broadening in magnetic fields for x=0.08, while it shifts toward the low-temperature side in parallel with increasing field for x=0.11 and 0.12 where the charge-spin stripe order is formed at low temperatures. As for x=0.10, the broadening is observed in low fields and it changes to the parallel shift in high fields above 9 T. Moreover, the normal-state value of ρ _ab at low temperatures markedly increases with increasing field up to 15 T. It is possible that these pronounced features of x=0.10 are understood in terms of the magnetic-field-induced stabilization of the stripe order suggested from the neutron-scattering measurements in the La-214 system. The ρ _ab in the normal state at low temperatures has been found to be proportional to ln(1/T) for x=0.10, 0.11, and 0.12. The ln(1/T) dependence of ρ _ab is robust even in the stripe-ordered state.