We have investigated the magnetoresistance (MR) of heterostructures containing near-surface two-dimensional electron systems subject to periodic, sign-alternating magnetic fields produced by arrays of sub-micron ferromagnetic stripes fabricated on the device surface. We observe giant magnetoresistances (GMR) with up to a ∼ 1000% increase in resistance on application of external fields of only ∼ 100 mT at a temperature of 4 K and ∼ 1% at 300 K. The MR is strongly dependent upon the angle between the external field and the stripes and it can also be strongly hysteretic. This MR arises from the electrons propagating in open ‘snake’ orbits along the lines of zero magnetic field. Such devices may have possible applications as magnetic memories and sensors.
Overend, N., Nogaret, A., Gallagher, B. L., Main, P. C., Henini, M., Wirtz, R., Newbury, R., Marrows, C. H., Howson, M. A., & Beaumont, S. P. (1998). Observation of giant magnetoresistances in hybrid semiconductor/ferromagnetic devices. Journal of Magnetism and Magnetic Materials, 177 - 181(Part 2), 898-899. https://doi.org/10.1016/S0304-8853(97)00734-8