Numerical Analysis of the Nonlinear Excitation of Subcritical Spin-Wave Modes Within a Micromagnetic Framework

A micromagnetic analysis of the excitation of subcritical bullet modes by spin-polarized currents in magnetic nanocontact systems is carried out by taking into account the contributions arising from Oersted and thermal fields. It is demonstrated that the former yields an increase of the value of the excitation thresholds, whereas the latter represents the source of the nonlinear fluctuations needed to excite such subcritical modes.