Electron transport in ferromagnet/InAs hybrid devices

Electron transport in ferromagnet/InAs hybrid metal-oxide semiconductor field-effect transistors is investigated at liquid helium temperature. We employ p-type InAs crystals which exhibit two-dimensional electron systems at their surfaces. In transistors with non-magnetic contacts Shubnikov-de Haas oscillations as well as weak localization effects in the longitudinal resistance hint at a strong and tunable spin-orbit interaction. Permalloy source and drain contacts with defined micromagnetic behavior have been integrated in ferromagnet/InAs hybrid transistors. These transistors exhibit a tunable magnetoresistance effect which is examined in external magnetic fields as a function of the gate voltage.