Hysteretic magneto-transport of a High-T$_{c}$ superconducting/ferromagnetic multilayer with tunable magnetic domain structure

The magneto-transport of a hybrid heterostructure combining a YBaCuO$_{7-\delta }$ thin film and a Co/Pt superlattice shows an unusual hysteretic behavior. Depending on the angle between the external applied field and the film plane, and on the magnetic history, either a increase or a decrease of the mixed-state resistance is observed. The combination of magneto-transport, magnetic force microscopy and anomalous Hall effect measurements allows us to correlate these effects to the magnetic domain structures in the Co/Pt superlattice. We unequivocally prove that the hysteretic magneto-transport is induced by the stray magnetic fields from tunable magnetic domain structures, which may induce vortices or produce vortex pinning, leading to the increase/decrease of the mixed-state resistance. Work supported by French ANR ``Superhybrids-II'' and RTRA ``Supraspin'' grants.