Layer-resolved imaging of domain wall interactions in magnetic tunnel junction-liketrilayers

Abstract

We have performed a layer-resolved, microscopic study of interactions between domainwalls in two magnetic layers separated by a non-magnetic one, using high-resolution x-rayphotoemission electron microscopy. Domain walls in the hard magnetic Co layer of aCo/Al2O3/FeNi trilayer with in-plane uniaxial anisotropy strongly modify the local magnetization directionin the soft magnetic FeNi layer. The stray fields associated with the domain walls lead toan antiparallel coupling between the local Co and FeNi moments. For domain walls parallelto the easy magnetization axis, this interaction is limited to the domain wall region itself.For strongly charged (head-on or tail-to-tail) walls, the antiparallel coupling dominates theinteraction over radial distances up to several micrometres from the centre of the domainwall.