Transport in superconductor/ferromagnet multilayers with Néel-type domain walls*

We experimentally investigate the coupling between magnetization reversal and magneto-transport in the metallic superconductor/ferromagnet multilayers. The ferromagnet consists itself of a multilayer in which the materials’ stack (Co, Pt, Ir and Ru) is engineered in order to tailor i) the magnetic domains morphology and ii) their size. These variables have a striking effect on the magneto-transport properties below the superconducting critical temperature. In particular, in the presence of magnetic domains the mixed-state resistance is radically diminished to an extent that depends on the domains structure morphology. Contrarily, when the ferromagnet is saturated, an excess resistance is observed. Furthermore, and interestingly, those changes in the longitudinal resistance are accompanied by an anomalous transverse resistance which strongly depends on the applied magnetic field direction and magnetic history. We will discuss the mechanisms contributing to that behavior, which include Pearl vortex pinning and generation, as well as inhomogeneous superconductivity induced by the magnetic template.