We describe the process of multiscale modelling of magnetic materials, based on atomistic models coupled parametrically to micromagnetic calculations. At the atomistic lengthscale we use Spin Dynamics (SD) to study switching mechanisms, using structures predicted by Molecular Dynamics. The process is completed using SD to calculate the cell size and temperature dependent parameters for micromagnetic calculations. We demonstrate an unusually strong cell size scaling for Nd 2 Fe 14 B, and demonstrate numerically the existence of atomic scale Barkhausen jumps during magnetization switching. Scaling of magnetic properties is shown to be important in micromagnetic calculations of hysteresis, especially considering variation in micromagnetic cell size.

We investigated the atomic fill site probability distributions across supercell structures of RT12-xTi (R=Nd, Sm, T=Fe, Co). We use a combined molecular dynamics and Boltzmann distribution approach to extrapolate the probability distributions for Ti substitution from lower to higher temperatures with an equilibrium condition to assess how temperature affects the predictability of the structures fill path. It was found that the Nd and Sm based Fe systems have the highest filling probability path at lower temperatures but the cohesive energy change due to Ti substitution in Sm and Nd based crystals indicates that a more stable system could be achieved with a combination Co and Fe in the transition metal site.

This is a repository copy of Atomistic simulations of α-Fe /Nd2Fe14B magnetic core/shell nanocomposites with enhanced energy product for high temperature permanent magnet applications.

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