抄録
The results of the thermomagnetic investigation of two natural pyrrhotites of intermediate chemical composition indicate the co-existence of (1) a ferrimagnetic phase of estimated composition Fe0.875S to Fe0.88S (Tc≈300°C) and (2) an antiferromagnetic phase which becomes ferrimagnetic above 180°C due to. vacancy ordering (Tc between 250 and 275°C). The second phase comprises 70 to 90% of the individual specimens, and is less Fe deficient than the composition of the whole samples. These conclusions were largely confirmed by the results of the application of magnetite powder to etched polished surfaces of the samples. Changes in thermomagnetic properties of both phases are observed after continued heating of the specimens above about 250°C. Heating of the specimens to 500-600°C probably results in homogenization of the specimens as the points of inflection below 300°C on the J(T) curves disappear.
