Anisotropy of Domain Wall Resistance

The resistive effect of domain walls in FePd films with perpendicular anisotropy was studied experimentally as a function of field and temperature. The films were grown directly on MgO substrates, which induces an unusual virgin magnetic configuration composed of 60 nm wide parallel stripe domains. This allowed us to carry out the first measurements of the anisotropy of domain wall resistivity in the two configurations of current perpendicular and parallel to the walls. At 18 K, we find $8.2\%$ and $1.3\%$ for the domain wall magnetoresistance normalized to the wall width (8 nm) in these two respective configurations. These values are consistent with the predictions of Levy and Zhang.