  We investigate the effect of strong spin-orbit interaction on the electronic
transport through non-magnetic impurities in one-dimensional systems. When a
perpendicular magnetic field is applied, the electron spin polarization becomes
momentum-dependent and spin-flip scattering appears, to first order in the
applied field, in addition to the usual potential scattering. We analyze a
situation in which, by tuning the Fermi level and the Rashba coupling, the
magnetic field can suppress the potential scattering. This mechanism should
give rise to a significant negative magnetoresistance in the limit of large
barriers.
