Oscillatory magnetoresistance in a quantum wire spin valve: A means to estimate the saturated drift velocity or mobility of carriers

Abstract

We show that the magnetoresistance of a quasi one-dimensional spin valve structure is oscillatory in a magnetic field applied along the axis of the structure, as long as the ferromagnetic layers of the spin valve are magnetized in a direction perpendicular to the magnetic field. The oscillation period allows us to estimate the drift velocity of carriers (either majority or minority carriers) in the paramagnetic layer. From that, one can estimate the majority or minority carrier drift mobilities if the velocity is not saturated. In the saturated velocity regime, one can estimate the majority or minority carrier saturation velocities. These quantities are usually difficult to measure otherwise, particularly for minority carriers.