Atomistic Spin Model Simulations of Magnetic Nanomaterials
Atomistic spin models model magnetic materials at the atomic scale, treating each magnetic atom as possessing a local magnetic moment. They are particularly useful in simulating high temperature properties of materials, the effects of defects, ultrafast spin dynamics, exchange bias and other phenomena. In our new article "Atomistic spin model simulations of magnetic nanomaterials" published in Journal of Physics: Condensed Matter, we review the physical foundations of atomistic spin models, their implementation in algorithmic form, and a series of computational tests to validate their correctness. The algorithms are implemented in the open-source VAMPIRE software package (vampire.york.ac.uk), enabling wider use and adoption of atomistic models. Due to the high resolution of the atomistic model, calculation of the demagnetising fields with a macrocell approximation is treated in detail and excellent agreement is found for some analytical results. In addition, the complexity of the atomistic model means that simulations are computationally expensive, and so details of the parallelisation of the VAMPIRE code are presented, showing excellent scaling for a wide range of problems.