Combined Molecular and Spin Dynamics Simulation of BCC Iron with Defects

Using an atomistic model that handles translational and spin degrees of freedom, combined molecular and spin dynamics simulations have been performed to study BCC iron containing vacancy defects. Atomic interactions are described by an empirical many-body potential while spin interactions are handled by a Heisenberg-like coordinate dependent exchange interaction. We analyze space-displaced, time-displaced correlation functions to investigate phonon and magnon excitations[1]. We show that the introduction of randomly distributed vacancies causes a decrease in magnon frequency as well as a broadening of the excitation peaks[2]. We show that clustered vacancy defects induce novel excitation modes which are localized within the vicinity of the defect, becoming more distinct from bulk excitations with increasing defect size.


1 - D. Perera, et al, J. Appl. Phys. 115, 17D124 (2014)
2 - E. C. Svensson, et al, Solid State Comm. 7, 1693 (1969)