A general, microscopic model of B20 magnets

Materials belonging to the B20 family are prominent in the study of exotic magnetism, including notable examples of helical magnetism and skyrmion lattice phases. Contemporary research continues to reveal intricacies of the low-temperature magnetic ordering of these materials, some of which are observed in only a subset. To properly account for these complexities, one requires a more in-depth description of these materials than is typical.

In contrast to the standard continuum model used to describe these materials, we introduce a general, symmetry-invariant, microscopic model of nearest-neighbour exchange interactions constructed through group theoretical means. This model is determined up to the relative strength of nine model terms. Computational studies using the Effective Field Method are also presented and provide intuition into the role of each model term in determining the magnetic order of these materials. These simulations reveal atomic-scale features which are not adequately described by continuum models.