Spin torque and critical currents for magnetic vortex nano-oscillator in nanopillars

TL;DR

This paper models the dynamic behavior of magnetic vortex oscillations in nanopillars induced by spin-polarized currents, providing theoretical predictions for key parameters like frequency and current thresholds.

Contribution

It introduces a generalized Thiele approach to describe vortex excitations, accounting for non-linear effects and linking parameters to physical properties of the system.

Findings

Calculated current ranges for vortex oscillations

Predicted oscillation frequencies and orbit radii

Provided a model for experimental validation

Abstract

We calculated the main dynamic parameters of the spin polarized current induced magnetic vortex oscillations in nanopillars, such as the range of current density, where a vortex steady oscillations exist, the oscillation frequency and orbit radius. We accounted for both the non-linear vortex frequency and non-linear vortex damping. To describe the vortex excitations by the spin polarized current we used a generalized Thiele approach to motion of the vortex core as a collective coordinate. All the calculation results are represented via the free layer sizes, saturation magnetization, Gilbert damping and the degree of the spin polarization of the fixed layer. Predictions of the developed model can be checked experimentally.