It is not sufficient to state that a crystal is ‘magnetic’. The type of magnetic order has to be specified too. We’ll examine a few of the typical situations. After this video, you will be able to tell the difference between ferromagnetism, ferrimagnetism, antiferromagnetism, spin spirals and non-collinear magnetism. And — given a sufficient amount of computing time — you’ll be able to figure out which of a given set of types of magnetic order is the energetically most favourable one for a given crystal.
Depending on your taste, mood or time, you can pick one (or more) of the following tasks. If you have problems or questions during these tasks, please post them in the forum (and/or help others by answering).