Current-control of chaos and effects of thermal fluctuations in magnetic tunnel junctions

TL;DR

This paper theoretically explores how thermal fluctuations influence chaotic magnetization dynamics in magnetic tunnel junctions, demonstrating control via DC current bias and implications for brain-inspired computing.

Contribution

It introduces a theoretical framework linking thermal noise, chaos, and current control in MTJs with perpendicular magnetic anisotropy.

Findings

Thermal fluctuations induce chaos in MTJ magnetization dynamics.

Chaos can be controlled using DC current bias.

Thermal noise facilitates noise-induced chaos.

Abstract

We theoretically investigate the chaotic behavior of spin-torque ferromagnetic resonance in magnetic tunnel junctions (MTJs) with perpendicular magnetic anisotropy under thermal fluctuations. By calculating the Lyapunov exponent based on the Landau-Lifshitz-Gilbert equation, we demonstrate that an MTJ characterized by a double-well potential, composed of uniaxial magnetic anisotropy and an external magnetic field, exhibits chaotic magnetization dynamics that can be controlled by means of the DC current bias. Furthermore, we find that thermal fluctuations help to induce these chaotic magnetization dynamics, which can be regarded as noise-induced chaos. This research provides a basis for brain-inspired computing using spintronic devices and advances the understanding of the interplay between thermal fluctuations and chaos in magnetization dynamics.