Complex magnetic phase diagram and skyrmion lifetime in an ultrathin film from atomistic simulations

TL;DR

This study maps the magnetic phase diagram of an ultrathin PdFe bilayer on Ir(111) using atomistic simulations, revealing ordered phases, a fluctuation-disordered phase with skyrmions, and their temperature-dependent lifetimes.

Contribution

It provides a detailed phase diagram and insights into skyrmion stability and lifetime in an ultrathin film through combined ab initio and simulation methods.

Findings

Identified three ordered magnetic phases at low temperatures.

Discovered a fluctuation-disordered phase with skyrmions at intermediate temperatures.

Skyrmion lifetime follows Arrhenius law as temperature varies.

Abstract

We determined the magnetic B-T phase diagram of PdFe bilayer on Ir(111) surface by performing Monte Carlo and spin dynamics simulations based on an effective classical spin model. The parameters of the spin model were determined by ab initio methods. At low temperatures we found three types of ordered phases, while at higher temperatures, below the completely disordered paramagnetic phase, a large region of the phase diagram is associated with a fluctuation-disordered phase. Within the applied model, this state is characterized by the presence of skyrmions with finite lifetime. According to the simulations, this lifetime follows the Arrhenius law as a function of temperature.