Magnetotransport study of the charged stripes in high-T-c cuprates

We present a study of the in-plane and out-of-plane magnetoresistance (MR) in heavily-underdoped, anti-ferromagnetic YBa2Cu3O6+x, which reveals a vari ety of striking features. The in-plane MR demonstrates a "d-wave"-like anis otropy upon rotating the magnetic field H within the ab plane. With decreas ing temperature below 20-25 K, the system acquires memory: exposing a cryst al to the magnetic field results in a persistent in-plane resistivity aniso tropy. The overall features can be explained by assuming that the CuO2 plan es contain a developed array of stripes accommodating the doped holes, and that the MR is associated with the field-induced topological ordering of th e stripes.