TEMPERATURE-DEPENDENT MAGNETIC-SUSCEPTIBILITY OF MARCASITE (FES2)

The magnetic susceptibility χ of a natural sample of marcasite (FeS2) has been measured with a Faraday balance in the temperature range 4.2-380 K. For T<150 K, the data follow the expression 106χ=64+(787T) cm3/mole, where the Curie-type contribution is from a magnetic impurity. For T>180 K, χ increases weakly with increasing T. The estimated χ for pure marcasite varies from 64 × 10-6 cm3/mole at 4.2 K to 68 × 10-6 cm3/mole at 380 K. The observations suggest a low-spin configuration for Fe2+ in marcasite leading to Van Vleck paramagnetism, similar to the case of iron pyrite. Some details of the Faraday balance used in these studies are also given. © 1979 The American Physical Society.