Switching the magnetic configuration of a spin valve by current-induced domain wall motion

We present experimental results on the displacement of a domain wall by injection of a dc current through the wall. The samples are 1-mum-wide long stripes of a CoO/Co/Cu/NiFe classical spin-valve structure. The stripes have been patterned by electron-beam lithography. A neck has been defined at 1/3 of the total length of the stripe and is pinning center for the domain walls, as shown by the steps of the giant magnetoresistance curves at intermediate levels (1/3 or 2/3) between the resistances corresponding to the parallel and antiparallel configurations. We show by electric transport measurements that, once a wall is trapped, it can be moved by injecting a dc current higher than a threshold current of the order of magnitude of 10(7) A/cm(2). We discuss the different possible origins of this effect, i.e., local magnetic field created by the current and/or spin transfer from spin-polarized current. (C) 2002 American Institute of Physics.