Abstract:
The dynamical behavior of the magnetism of diluted magnetic semiconductors (DMS) has been investigated. Atomistic spin dynamics simulations were done for 5% Mn-doped GaAs with various concentrations of As antisite defects. The magnetization curve, M(T), and the Curie temperature Tc have been calculated, and are found to be in good correspondence to results from Monte Carlo simulations and experiments. Equilibrium and non-equilibrium behavior of the magnetic pair correlation function have been extracted. 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. It is shown that dynamics is governed, to a large degree, by the damping parameter in the equations of motion and the system size.

Ref: Phys. Rev. B 78, 144419 (2008), Phys. Rev. B 79, 024411 (2009)