Resistance behavior of metallic nanostructures fabricated by electron beamlithography

We report on magnetoresistance measurements of metallic nanostructures fabr icated by electron beam lithography carried out within a conventional scann ing transmisson electron microscope. Cold-wires of various widths between 5 0nm and 50 mu m exhibit a positive magnetoresistance the strength of which is increasing with decreasing wire width. This can be explained by the diff usive motion of electrons which are coherently backscattered. With decreasi ng width of the gold wires the backscattering rate increases leading to one -dimensional transport behavior of electrons. For gold wires with sidewise attached loops we observe the onset of resistance oscillations which is a d irect manifestation of the wave character of electrons in matter. Magnetic nanowires (Co) exhibit a negative magnetoresistance as originating from spi n-orbit scattering processes (anisotropic magnetoresistance). We present da ta which allow to determine the coercivity field of Co-wires.