Micromagnetic Modeling of Magnetization Dynamics Driven by Spin-Polarized Current: Analysis of Nonconfined Systems

We present a brief overview of the magnetization dynamics driven by a spin-polarized current in nonconfined ferromagnetic multilayers when a point-contact setup is used. The possibility to sustain persistent oscillations in these systems could be employed in the design of currentcontrolled microwave oscillators on nanometric scale. The attempt to reproduce the main experimental results by means of both macrospin and micromagnetic models encounters many difficulties. We have focused on the latter, summarizing the state-of-art and pointing out the still unsolved methodological problems arising from such a modeling.