Multilayer configuration for experiments of spin precession induced by a dc current

Until now, most predictions about spin precession induced by a CPP dc current have concerned a simple "asymmetric" configuration consisting of a free magnetic layer and of a thicker pinned magnetic layer. In the present work, we propose a different configuration where the precessing free magnetic layer is sandwiched between two thicker pinned magnetic layers having opposite magnetizations. In this "antisymmetric" configuration, the spin current and accumulation arising from expansion/contraction are nearly three times as large as in the asymmetric configuration, for given current and layer thickness. Moreover, both interfaces of the free magnetic layer are now active to generate drive torques. This should result in a reduction of the critical current density needed for spin oscillations, by a factor of about six. (C) 2003 American Institute of Physics.