Conventional superconductorlike behavior of the superconducting transition of La_2-xSr_xCuO₄(x ∼ 0.12) in magnetic fields

The superconducting transition in the electrical resistivity has been examined for La_2-xSr_xCuO4 (x ∼ 0.12) single crystals in magnetic fields. The broadening of the transition width in high fields is small compared to the case of the optimum doping (x ∼ 0.15) and the transition curve as a function of the temperature in each magnetic field shifts to lower temperature in almost parallel with applying magnetic field similar to the case of conventional superconductors. These results indicate that the superconducting fluctuation is weakened and that the coherence length in the CuO₂plane becomes much longer around x=0.12. The measurement results are discussed in relation to the appearance of long-range magnetic order.