Hall Noise and Transverse Freezing in Driven Vortex Lattices

We study driven vortex lattices in superconducting thin films. Above the critical force F{sub c} we find two dynamical phase transitions at F{sub p} and F{sub t} , which could be observed in simultaneous noise measurements of the longitudinal and Hall voltage. At F{sub p} there is a transition from plastic flow to smectic flow, where the voltage noise is isotropic (Hall noise = longitudinal noise) and there is a peak in the differential resistance. At F{sub t} there is a sharp transition to a frozen transverse solid, where the Hall noise falls abruptly and vortex motion is localized in the transverse direction. {copyright} {ital 1999} {ital The American Physical Society}