Huge tunnelling anisotropic magnetoresistance in (Ga,Mn)As nanoconstrictions

Abstract

We report here large anisotropic magnetoresistance (AMR) behaviours in single lateral (Ga,Mn)As nanoconstrictions of up to 1300%, along with large multistable telegraphic switching. The nanoconstriction devices are fabricated using high-resolution electron beam lithography of a 5nm thick (Ga,Mn)As epilayer. The unusual behaviour exhibited by these devices is discussed in the context of existing theories for enhanced AMR ferromagnetic semiconductor nanoscale devices, particularly with regard to the dependence on the magnetotransport of the bulk material. We conclude that our results are most consistent with the Coulomb blockade AMR mechanism. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.