Domain wall trapping probed by magnetoresistance and magnetic force microscopy in submicron ferromagnetic wire structures

Abstract

The magnetoresistance (MR) and domain structure of submicron NiFe wires and crosses fabricated using advanced electron beam lithography techniques have been studied in order to investigate the dependence of MR on the detailed domain configurations. While the 0.5 μm wire shows almost no longitudinal MR, the cross sample clearly shows a variation of the resistance upon sweeping the magnetic field, indicating an MR effect associated with the domain structures which form at the junction. By correlating the MR curves with the domain configurations obtained from magnetic force microscopy, we found that a 180° domain wall trapped in the junction of this 0.5 μm cross contributes a negative MR effect.