MAGNETORESISTANCE IN THE NORMAL-STATE OF LA1.925SR0.075CUO4+DELTA

The in-plane magnetoresistance of a high-quality single crystal of La1 .925Sr0.075CuO4+delta has been measured in both the high-symmetry tran sverse geometry and in the longitudinal geometry. In both orientations , the magnetoresistance is positive and shows conventional weak-field behavior. The measured longitudinal magnetoresistance, however, is fou nd to be almost an order of magnitude smaller than the measured transv erse magnetoresistance. A semiphenomenological theory based on anisotr opic scattering from hypothesized hole-pocket Fermi surfaces is introd uced, which can account for the latter positive effect, as well as for known Hall-effect measurements. We predict that, in the limit corresp onding to perfectly coherent in-plane hole motion along (pi,pi), there should be no saturation effect in the high-symmetry transverse magnet oresistance.