Resonances in hybrid magnetic/semiconductor electron waveguides

Summary form only given A number of groups have used nanofabrication techniques to study hybrid magnetic/semiconductor structures. Such devices have potential applications in memory/logic elements, nano-magnetometers and magnetic field sensors. A small-scale ferromagnetic element has been patterned onto a GaAs/AlGaAs heterostructure. The 2 dimensional electron gas has a depth of 40nm and an electron density of 4.1/spl times/10/sup 15/m/sup -2/. The devices were fabricated by evaporating a permalloy element along the current direction on top of a Schottky gated Hall bar. The Hall bar was patterned using standard e-beam lithography and lift off techniques. The positioning of the magnetic element is such that one end is at the centre of the Hall cross, the other end towards the end of the Hall bar. The devices were studied with an applied field perpendicular to the plane of the magnetic element, and at a tilt of 70/sup o/ between the field and the length of the element. Measurements were taken for a range of gate voltages and applied fields at temperatures down to 1.4K.