Tunable magnetoresistance in InAs/ferromagnet hybrid devices

Metal-oxide semiconductor field-effect transistors with ferromagnetic source- and drain-electrodes are fabricated on InAs. Tailored micromagnetic behavior of the ferromagnetic electrodes is achieved by use of a specific shape as well as in-plane external magnetic fields and is measured by magnetic-force microscopy. The field-effect in transistors with electrodes of defined magnetization is determined as a function of the gate voltage. The amplitude and the sign of abrupt resistance changes observed at points of irreversible switching of the ferromagnetic contacts' magnetization can be tuned by the gate voltage providing evidence for spin-polarized transport.