Abstract
Current-induced magnetic excitations in bilayer nanopillars ( in diameter) have been studied experimentally at low temperatures for large applied fields perpendicular to the layers. At sufficiently high current densities excitations, which lead to a decrease in differential resistance, are observed for both current polarities. Such bipolar excitations are not expected in a single domain model of spin transfer. We propose that at high current densities strong asymmetries in the spin accumulation cause spin-wave instabilities transverse to the current direction in bilayer samples, similar to those we have reported for single magnetic layer junctions.
- Received 25 June 2004
DOI:https://doi.org/10.1103/PhysRevB.71.140403
©2005 American Physical Society