Frustration and order driven by Hund’s rule coupling in antiferrromagnets

We discuss a simplified version of a recently proposed Hamiltonian to describe the case when the super-exchange interaction between different atomic orbitals leads to frustration because of Hund’s rule coupling. Using spin-wave theory, we demonstrate that while this is a rather simple model which can be studied by more elaborate techniques, it contains the essential elements of the physics present in real materials and leads to possible novel magnetic phases.