Computational approach to finite size and shape effects in iron nanomagnets

We examine a computational approach to the calculation of finite size and shape effects to magnetic systems based on the spin wave approximation to a Heisenberg ferromagnet. The method can be used for high throughput analysis of a variety of nanomagnetic materials. We compute the dependence of the magnetization of an iron nanomagnet on temperature, size and shape. The approach is applied to magnets in the range of 432 atoms to 59 million atoms, a size which is several orders of magnitude beyond the scalability of density functional theory.