Experimental evidence of the decoupling line in (Bi1.64Pb0.36)Sr-2(Ca0.79Y0.21)Cu2O8+delta single crystals by resistivity measurements - art.no. 184504

Both in-plane (rho (ab)) and out-of-plane (rho (c)) resistivity measurement s have been carried out on (Bi1.64Pb0.36)Sr-2(Ca0.79Y0.21)Cu2O8 + delta sin gle crystals with magnetic field applied along the c-axis direction. Studyi ng the temperature dependence of the resistivity ratio rho (ab)/rho (c), we identify at high temperature a pancake phase with the signature proposed b y Koshelev. At lower temperature, we observe a thermally activated behavior which can be interpreted easily in the framework of a three-dimensional vo rtex loops model. We found that the high-temperature limit of the thermally activated behavior corresponds to the low-temperature limit of the Koshele v's prediction. This latter is also characterized by an onset of the in-pla ne resistivity drop. Consequently, our data suggest that this line is a dim ensional crossover which describes the decoupling of the liquid state into a decoupled pancake state.