PUB - Publikationen an der Universität Bielefeld

Co nanowires of T-shaped geometry with and without nanoconstrictions are fabricated by means of electron beam lithography (EBL) followed by electron beam evaporation. We have succeeded in minimizing the width of the nanoconstriction, i.e., the nanocontact, down to 6 nm. In a subsequent second EBL process, gold contact leads are attached as close as possible to the nanoconstrictions, which allows us to measure the magnetoresistance (MR) of the sample as a function of the nanocontact width. We found that the MR of the T-shaped nanowires without a nanoconstriction can exclusively and quantitatively be explained by the anisotropic magnetoresistance of the Co nanowires. This allows us to separate the MR contribution of the nanoconstriction from the total MR of the sample quantitatively. We find that the resistance of the nanoconstriction is independent of the width of the nanocontact, whereas the corresponding MR contributions fluctuate depending on the various shapes of the nanoconstriction.