In a crystal of the fluorite structural group, BaF, in a helium atmosphere with small additions of fluorine and oxygen, paramagnetic complexes NiFFO (C), were synthesized by diffusion from the surface, which represent a stable associate of a trivalent nickel ion with an interstitial oxygen ion, O . The study of the molecular structure of the synthesized complexes was carried out by the electron paramagnetic resonance method at frequencies of 9.65, 34.35 and 94- 265 GHz, and in the temperature range from 5 to 120K . It was shown that the studied complex is formed by Ni(3d,F,S = 3/2) and O(2p,P, S = 1/2) ions. The Ni ion replaces the Ba lattice cation in the crystal, and the O ion is located in the adjacent interstitial site in one of the 001 crystallographic directions. It was established that in the synthesized complexes between Ni and O ions, a ferromagnetic exchange interaction was realized.
Ulanov et al. (2025) studied this question.