Spin dynamics simulation of topological CrPt₃ and Co₂MnGa magnetic nanoparticles

Magnetic nanoparticles have the potential for a variety of applications in medicine, energy, and computing. However, the intersection of nanoparticles and topological magnetic materials is relatively unexplored; typical studies of nanoparticles focus on the small-size, superparamagnetic regime, while studies of topological magnetic materials often focus on bulk-like scales. We use spin dynamics simulations to investigate the crossover from superparamagnetic to single domain topological magnetic states in CrPt₃ and Co₂MnGa nanoparticles. CrPt₃ and Co₂MnGa display nontrivial topology in their electronic structure, leading to strong spin-orbit states at the nanoparticle surface due to structural inversion asymmetry. Because Fe₃O₄ nanoparticles are extensively studied, we utilize them to compare the viability of our topological magnetic nanoparticles results. We simulate five nanoparticle shapes with sizes varying from 1 to 60 nm using the LLG equation dependent on external field sweeps at finite temperatures. Parameters for the Heisenberg exchange, surface DMI, and anisotropy were all obtained from first-principle calculations. Our work presents some of the first results for an entirely new regime of magnetic nanoparticles and could seed novel fields of magnetization studies.