Structure and physical properties of natural sphalerites and galena from the Dal'negorsk deposit in the temperature range 4-300 K

The structure and physical properties of natural sphalerites and galena from the Dal'negorsk ore massif were investigated. A nonlinear temperature dependence of the unit-cell parameters of sphalerite in the range 80-300 K was established by X-ray diffraction. The microstructure and elemental composition of sphalerites with different iron contents were studied. The results show that an increase in iron content in sphalerite solid solution leads to an increase in the unit-cell parameters. It is found that sphalerites are insulators in the temperature range from 4 to 300 K, as their absolute electrical resistivity is greater than 1 MOhmm. The temperature dependence of sphalerite magnetization has a peak corresponding to the mineral transition from antiferromagnetic to ferrimagnetic state with a Neel temperature of about 90 K in fields of 0, 0.15, and 1.00 T. The magnetic state of natural galena is due to a sphalerite impurity: The extrema in the temperature magnetization curve are typical of sphalerite.