111 research outputs found
Narrow channel Si-MOSFETs for electron transport studies
We have fabricated narrow channel Si-MOSFETs for electron transport studies at low temperature. The fabrication process combines optical lithography for large structures and high resolution e-beam lithography for narrow gates. The smallest working devices have a 0.14 ÎĽm wide gate. This paper reports the fabrication process and gives some examples of the quantum transport phenomena observed in these devices
Nanoconstriction Microscopy of the Giant Magnetoresistance in Cobalt/Copper Spin Valves
We use nanometer-sized point contacts to a Co/Cu spin valve to study the
giant magnetoresistance (GMR) of only a few Co domains. The measured data show
strong device-to-device differences of the GMR curve, which we attribute to the
absence of averaging over many domains. The GMR ratio decreases with increasing
bias current. For one particular device, this is accompanied by the development
of two distinct GMR plateaus, the plateau level depending on bias polarity and
sweep direction of the magnetic field. We attribute the observed behavior to
current-induced changes of the magnetization, involving spin transfer due to
incoherent emission of magnons and self-field effects.Comment: 13 pages [pre-print style], 3 figures, accepted AP
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