Magnetoresistance in nanocontacts formed in NiFe thin films

Magnetoresistance (MR) and current-driven conductance change measurements in NiFe nanocontacts in ion-beam-sputtered thin films at the initial growth stage were performed. A MR ratio of as large as about 140% with about 1 nm 2 contact whose conductance change was the same as that of current-driven measurements was observed. Furthermore, as it aligned so well in the empirical fit of the contact size dependence to MR ratio based on the previous reports, it was deduced that domain wall plays an important role with respect to the large MR.