Strong Hall voltage modulation in hybrid ferromagnet/semiconductor microstructure

We present a new magnetoelectronic device consisting of a mu m-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-perpendicular to(r), which induces a Hall resistance, R-H,in the microjunction. External application of a weak in-plane magnetic field reverses the magnetization of the ferromagnet and with it B-perpendicular to(r), thus modulating R-H. 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. (C) 1997 American Institute of Physics.