Classical magnetoresistance in a curved wire

Abstract

The semiclassical magnetoresistance due to the Lorentz force is computed for current flowing in a curved wire in the form of a two-dimensional annulus. The surface scattering is taken to be diffuse, and the bulk scattering is s wave and elastic. Near zero magnetic field the resistance has a minimum instead of the maximum in a straight wire. The resistance continues to decrease until it reaches a local minimum at a field corrseponding to a cyclotron radius in between the inner radius and the outer radius of the annulus. Thus, in a curved wire the optimum magnetic field for reducing surface scattering is not zero field as for a straight wire, but a field which allows electrons to go part way around the curves. This result explains the negative magnetoresistance near zero field seen in systems contained curved wire segments and shows how geometry can be used to tune the semiclassical magnetoresistance in the regime where surface scattering dominates. © 2005 American Institute of Physics.