Atomistic spin dynamics of the Cu-Mn spin-glass alloy

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.