Absence of spin scattering of in-plane spring domain walls

Abstract

We have performed current perpendicular-to-plane measurements in Gd-transition metal multilayers and amorphous ${\mathrm{Co}}_{x}{\mathrm{Gd}}_{1\ensuremath{-}x}∕{\mathrm{Co}}_{y}{\mathrm{Gd}}_{1\ensuremath{-}y}$ bilayers. Both systems create in-plane exchange spring domain walls (SWs) whose width can be controlled by an external magnetic field. The results can be explained fully by Lorentz magnetoresistance (MR) plus the effect of the interface. They show no intrinsic scattering from the SWs, suggesting that the ``mistracking'' of the spin to the local magnetization is not the main cause of MR of domain walls but the change of spin populations across a thin barrier as in GMR structures.