Atomistic spin dynamics of the CuMn spin glass alloy

TL;DR

This paper uses Langevin spin dynamics simulations to study the relaxation and aging behavior of the CuMn spin glass alloy, combining first-principles calculations with dynamical modeling.

Contribution

It introduces a method integrating first-principles derived interactions with Langevin spin dynamics to analyze spin glass relaxation.

Findings

Dynamics depend on damping parameter and system size.

Aging regime observed for large damping and system size.

First-principles calculations inform the interaction parameters.

Abstract

We demonstrate the use of Langevin spin dynamics for studying dynamical properties of an archetypical spin glass system. Simulations are performed on CuMn (20% Mn) where we study the relaxation that follows a sudden quench of the system to the low temperature phase. The system is modeled by a Heisenberg Hamiltonian where the Heisenberg interaction parameters are calculated by means of first-principles density functional theory. Simulations are performed by numerically solving the Langevin equations of motion for the atomic spins. It is shown that dynamics is governed, to a large degree, by the damping parameter in the equations of motion and the system size. For large damping and large system sizes we observe the typical aging regime.