Spin‐wave excitation by spin‐polarized current in magnetic nanostructures

Abstract

A current‐driven magnetic point‐contact device can support both a quasi‐linear propagating spin‐wave mode and a nonlinear self‐localized evanescent spin‐wave bullet mode. In this work we show how the bias field orientation determines the nature of the excited modes. By using a micromagnetic framework we can describe the main properties of the observed modes, deriving also a satisfying agreement with analytical theories. It is also pointed out how the nature of these modes differs in: (i) threshold current of excitation, (ii) precession angle, (iii) frequency spectra, (iv) trajectory of the precessional motion, (v) spatial localization of the spin‐wave amplitude. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)