Magnetization of a pyrrhotite of composition Fe0.847S in area of a Curie point

The x-ray, Mossbauer and termomagnetic researches of pyrrhotites possessing high-temperature λ - peak (Тλ = 310 C) on curve dependence of magnetization on temperature - I (Т) are lead. The chemical compound and conditions of formation of such pyrrhotites is determined. It is established, that samples with λ - peak possessed the raised maintenance of sulfur in comparison with pyrrhotites Fe7S8 and corresponded to structure Fe1-nS (n=0.153). As has shown experiment, these pyrrhotites are in a metastable phase condition and in due course (samples were observed during 29 years) pass in a pyrite and a pyrrhotite of structure Fe7S8 (at the presence of an atmosphere the Goethite and a szomolnokit was formed also). Because of quantum-mechanical calculations of dependence of specific magnetization from temperature for various underlattices with various integral of exchange interaction good conformity of a settlement curve with experimental is received. Calculations were made within the framework of model of a molecular field for a two-sublattice ferrimagnetic.