Strain-induced magnetoresistance oscillations in GaAs-AlGaAs heterojunctions with ferromagnetic and superconducting submicrometer gratings

Abstract

We investigated the low-field magnetoresistance rho xx of a two- dimensional electron gas (2DEG) underneath ferromagnetic and superconducting metallic gratings. The strain due to the different thermal expansion coefficients of the metallic grating and the GaAs-AlGaAs heterojunctions results in a one-dimensional superlattice potential in the plane of the 2DEG. Depending on the aspect ratio of the gratings, different harmonics of the potential can be resolved in rho xx. The observed resistance anomalies can be modelled in a simple semiclassical model.