ANGULAR-DEPENDENCE OF THE C-AXIS NORMAL-STATE MAGNETORESISTANCE IN SINGLE-CRYSTAL TL2BA2CUO6

We report measurements of the normal state magnetoresistance (MR) from 30 to 340 K in fields B up to 13 T for single crystals of overdoped T l2Ba2CuO6 (T-c less than or equal to 25 K). For out-of-plane current f low, the transverse MR Delta rho(c)/rho(c) is large and positive. On r otating B within the a-b plane, Delta rho(c)/rho(c) exhibits a strikin g anisotropy with fourfold symmetry. The amplitude of this effect incr eases as B-4 and the maximum MR occurs for B along the [110] crystallo graphic directions, i.e., at 45 degrees to the Cu-O-Cu bonds. This the first direct evidence for anisotropy of the in-plane mean free path i n the cuprates.