Temperature dependence of large positive magnetoresistance in hybrid ferromagnetic/semiconductor devices

We investigate a new type of magnetoresistance(MR) in which the resistivity of a near-surface two-dimensional electron gas is controlled by the magnetization of a submicron ferromagneticgrating defined on the surface of the device. We observe an increase in resistance of up to ∼1500% at a temperature of 4 K and ∼1% at 300 K. The magnitude and temperature dependence of the MR are well accounted for by a semiclassical theory. Optimization of device parameters is expected to increase considerably the magnitude of the room temperature MR.