Vortex oscillations induced by a spin-polarized current in a magnetic nanopillar: Evidence for a failure of the Thiele approach

TL;DR

This paper studies vortex oscillations in magnetic nanopillars caused by spin-polarized currents, revealing limitations of the classical Thiele approach and proposing a new energy dissipation-based analytical method.

Contribution

It demonstrates the failure of the Thiele approach for vortex dynamics and introduces a validated alternative analytical technique based on energy dissipation calculations.

Findings

Damped vortex motion observed at low currents

Stationary vortex rotation identified

Vortex core switching occurs at higher currents

Abstract

We investigate the vortex excitations induced by a spin-polarized current in a magnetic nanopillar by means of micromagnetic simulations and analytical calculations. Damped motion, stationary vortex rotation and the switching of the vortex core are successively observed for increasing values of the current. We demonstrate that even for small amplitude of the vortex motion, the analytical description based the classical Thiele approach can yield quantitatively and qualitatively unsound results. We suggest and validate a new analytical technique based on the calculation of the energy dissipation.