Strong Hall voltage modulation in hybrid ferromagnet/semiconductor microstructures

We present a new magnetoelectronic device consisting of a mm-scale semiconductor cross junction and a patterned, electrically isolated, ferromagnetic overlayer with in-plane magnetization. The large local magnetic field emanating from the edge of the thin ferromagnetic film has a strong perpendicular magnetic component, B'(r), which induces a Hall resistance, RH , in the microjunction. External application of a weak in-plane magnetic field reverses the magnetization of the ferromagnet and with it B'(r), thus modulating RH . Our data demonstrate that this strong ‘‘local’’ Hall effect is operative at both cryogenic and room temperatures, and is promising for device applications such as field sensors or integrated nonvolatile memory cells. © 1997 American Institute of Physics. @S0003-6951~97!00747-X#