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 ferromagnetic grating defined on the surface of the device. We observe an increase in resistance of rip to similar to 1500% at a temperature of 4 K and similar to 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. (C) 1998 American Institute of Physics. [S0003-6951(98)03014-9].