Influence of current density on the magnetization process in active spin-valve elements

Simultaneous magnetoresistance measurements and observation of magnetic dom ain structures have been performed on active spin-valve elements by means o f in situ experiments in a Lorentz transmission electron microscope. Two di fferent spin-valve structures with NiFe and NiFe/Co sense layers have been studied with two sizes of rectangular elements. The effect of different app lied current values has been analyzed and the addition of a Co layer in the sense layer has a large influence on the spin-valve behavior and on the do main structure. Also, two different processes for magnetic domain growth an d motion have been observed for low or high applied current densities. (C) 1998 American Institute of Physics.