First principles theory of multipolar interaction in ferromagnetic rare-earth nitride

Microscopic theory of multipolar interaction between J-multiplets in f metal compounds is developed for an adequate description of Goodenough mechanism. The developed multipolar model is applied to reveal the multipolar nature of the ferromagnetism of NdN by combining the framework with first principles calculations. The multipolar interaction parameters of NdN were quantitatively determined up to nineth order. On this basis, the ferromagnetic phase was simulated. The phase was found to be characterized by seventh and nineth and many other higher order multipole moments. The manifestation of the multipole moment appears in spin-wave dispersion, which can be examined by inelastic neutron scattering measurements.