Really First Principles Calculations for CoF3

We have derived the low-energy electronic structure of CoF3, originating from the strongly-correlated 3d(6) system of the Co3+ ion, taking into account the crystal-field interactions, with a relatively weak trigonal distortion, and the relativistic spin orbit interaction. We have calculated from really first-principles the relevant crystal-field interactions. With the discrete electronic structure for 3d electrons we have described the magnetic properties (the value of the magnetic moment and its direction). The moment direction is determined by the local off-octahedral trigonal distortion proving the single-ion origin of the magnetocrystalline anisotropy. We evaluated the orbital moment and the strength of spin interactions responsible for the formation of the magnetic state. Our studies indicate that calculations of the electronic structure of a 3d compound for the physically-adequate description of the magnetic properties has to be performed at the meV scale.