Quantifying the thermal stability in perpendicularly magnetized ferromagnetic nanodisks with forward flux sampling

TL;DR

This paper uses forward flux sampling to accurately predict thermal stability and switching rates in perpendicularly magnetized nanodisks, revealing significant differences from traditional estimates and highlighting the impact of interfacial interactions.

Contribution

It introduces a simulation approach for rare thermally-activated magnetic transitions, providing more precise lifetime estimates considering domain wall dynamics and interfacial effects.

Findings

Switching rates depend on Dzyaloshinskii-Moriya interaction strength.

Lifetimes differ by orders of magnitude from traditional 1 GHz attempt frequency estimates.

Forward flux sampling effectively models rare magnetic transition events.

Abstract

The thermal stability in nanostructured magnetic systems is an important issue for applications in information storage. From a theoretical and simulation perspective, an accurate prediction of thermally-activated transitions is a challenging problem because desired retention times are on the order of 10 years, while the characteristic time scale for precessional magnetization dynamics is of the order of nanoseconds. Here, we present a theoretical study of the thermal stability of magnetic elements in the form of perpendicularly-magnetized ferromagnetic disks using the forward flux sampling method, which is useful for simulating rare events. We demonstrate how rates of thermally-activated switching between the two uniformly-magnetized ``up'' and ``down'' states, which occurs through domain wall nucleation and propagation, vary with the interfacial Dzyaloshinskii-Moriya interaction, which affect the energy barrier separating these states. Moreover, we find that the average lifetimes differ by several orders of magnitude from estimates based on the commonly assumed value of 1 GHz for the attempt frequency.