Point-contact studies of current-controlled domain switching in magnetic multilayers

We present measurements demonstrating current-induced magnetic domain switc hing, and also other magnetic excitations, in point-contact devices contain ing alternating ferromagnetic (F) and noble metal (N) layers, for perpendic ular currents similar to 10(9) A/cm(2). For F/N/F trilayers in which one F layer is much thinner than the other, we can controllably switch the magnet ic moments in the two F layers parallel with a current bias of one sign, an d switch them antiparallel with a reversed current. For thicker magnetic fi lms, and for thin films in the presence of a saturating magnetic field, we observe nonhysteretic current-induced changes in resistance, which can be u nderstood as current-induced spin-wave excitations. These observations are in agreement with a model of current-induced magnetic reorientations caused by local exchange forces between conduction electrons and the magnetic mom ents. (C) 2000 American Institute of Physics. [S0021-8979(00)65808-5].