In-plane and out-of-plane magnetoresistance in La2-xSrxCuO4 single crystals

The magnetoresistance of La2-xSrxCuO4 single crystals has been studied extensively over a wide composition range (0.07 less than or equal to x less than or equal to 0.28) using current parallel (in plane) and perpendicular (out of plane) to the CuO2 plane. In the underdoped superconducting phase (x similar to 0.10), the in-plane magnetoconductivity above T-c is well described as fluctuation conductivity but only with the Aslamasov-Larkin term. The negligibly small Maki-Thompson contribution is suggestive of anisotropic Cooper pairing. We find a pronounced negative and isotropic out-of-plane magnetoresistance at low temperatures in this composition range. In the optimally doped to the overdoped superconducting phases (0.15 less than or equal to x less than or equal to 0.20), a substantial normal-state component is observed in the in-plane magnetoresistance. The classical Kohler's rule appears to break down for the normal-state magnetoresistance, which supports the involvement of two distinct scattering rates tau(tr) and tau(H). In the out-of-plane magnetoresistance; we find an unconventional scaling Delta rho(c)/rho(c) proportional to(H/rho alpha)(2) for H perpendicular to J and (H/T)(2) for H parallel to J. In contrast to these anomalous behaviors, we find that Kohler's rule holds for both the in-plane and the out-of-plane transverse magnetoresistance in the overdoped normal metal region, implying a conventional anisotropic three-dimensional transport. These findings provide further evidence for the unconventional normal-state transport in the samples which exhibit high-T-c superconductivity.