Self-organization in the one-dimensional Landau-Lifshitz-Gilbert-Slonczewski equation with non-uniform anisotropy fields

TL;DR

This study numerically investigates how non-uniform anisotropy fields influence self-organization and localized dynamical states in one-dimensional spin-torque driven magnetic systems, revealing complex bifurcation structures.

Contribution

It introduces a numerical analysis of localized patterns and their bifurcations in a one-dimensional Landau-Lifshitz-Gilbert-Slonczewski model with antisymmetric anisotropy.

Findings

Identification of various dissipative states.

Observation of oscillatory and phase instabilities in localized patterns.

Phase diagram of bifurcations and dynamical regimes.

Abstract

In magnetic films driven by spin-polarized currents, the perpendicular-to-plane anisotropy is equivalent to breaking the time translation symmetry, i.e., to a parametric pumping. In this work, we numerically study those current-driven magnets via the Landau-Lifshitz-Gilbert-Slonczewski equation in one spatial dimension. We consider a space-dependent anisotropy field in the parametric-like regime. The anisotropy profile is antisymmetric to the middle point of the system. We find several dissipative states and dynamical behavior and focus on localized patterns that undergo oscillatory and phase instabilities. Using numerical simulations, we characterize the localized states' bifurcations and present the corresponding diagram of phases.