MEAM Seminar: “Thermalization of Bulk Magnetic Materials in Spin-Lattice Dynamics Simulations”

Spin-lattice dynamics (SLD), an increasingly popular simulation method which simultaneously computes both atomic displacements and spins, offer new possibilities for modeling the temporal evolution of systems where the coupling between these atomic features are relevant such as spin caloritronics, heat assisted magnetic recording, magnetocaloric responses and magnetic nanoparticle hyperthermia. To accurately model and understand these magnetic materials, SLD must capture spin-spin and spin-lattice interactions in a physically meaningful way. Recent work indicates that including a local magnetic anisotropy term in SLD simulations may be necessary to appropriately couple the magnetic spins to the atomic system to allow for thermal transport between the systems. A key obstacle to the adoption of this term is the lack of knowledge of its parameters for a broad range of materials. Ab initio calculations can obtain these parameters, but these calculations are limited by energy scales, system size and computational cost. A new framework using bulk experimental properties is introduced to obtain these parameters which avoids some or all of these challenges of the ab initio method. Results from this framework are discussed for iron along with the validation procedure for the found parameters.