Direct mapping of magnetoresistance to magnetic domain image in permalloy thin films by simultaneous measurement

Abstract

We report the first simultaneous measurements of the magnetoresistance (MR.) and the magnetic domain images in two-dimensional permalloy thin films by utilizing a magneto-optic magnetic microscope. In this way. we could directly map the MR to the domain patterns without any ambiguity For 30-nm-thick permalloy films with in-plane uniaxial magnetization, negative MR, was observed when the domain wall was nucleated. An analysis of the MR change with the anisotropic magnetoresistance resulted in a rather large domain wall thickness of 1.7 mu m compared to the well-known theoretical value of 0.3 mu m. We discuss possible origins of this discrepancy in terms of wide domain tails, wavy domain boundaries, and intrinsic properties associated with permalloy. This new method can be utilized to investigate the magnetic properties of newly emergent materials.