Magnetism of natural pyrrhotite, haematite and ilmenite

Summary

The paper deals with the magnetic properties of the natural minerals haematite, ilmenite and pyrrhotite. The natural remanent magnetization J_n, the volume susceptibility ℵ, the specific magnetization of saturation σ_so, the Curie temperature Θ, the A.C. demagnetization of natural remanent magnetization, the thermal demagnetization J_n, the temperature dependence of the specific magnetization of saturation, and several other parameters were determined for the individual sets of minerals. Since natural minerals can and do contain various heterogeneous and isomorphic admixtures, their magnetic properties may change depending on the content and type of these admixtures. Therefore, all the investigations of the magnetic properties described in this paper were carried out with extensive sets of minerals, representing various Czechoslovak and world localities. A number of interesting results were obtained from the executed experiments, e.g., the different stability of the natural remanent magnetization of haematite with respect to A.C. demagnetization, the presence and type of heterogeneous inclusions in ilmenite, the phase changes connected with the γ-transition in natural pyrrhotites, etc. The types of distributions of the investigated values of the magnetic properties were also determined.