Hydrogeochemistry and stable isotopes in radon-rich thermal waters of Belokurikha (Altai, Russia).

The first integrated isotope and chemistry results have been obtained for radon-rich thermal waters from the Belokurikha field which are used at a large spa resort in Altai, Russia. The waters reside in an unconfined aquifer composed of Quaternary soft sediments and in a confined (artesian) aquifer of monolithic to weathered Upper Paleozoic granites. The waters belong to three geochemical groups: low-radon nitrogen-silicic interstitial waters in weathered Paleozoic granites; groundwaters of REE-enriched and background compositions; surface waters of the Belokurikha River. The interstitial waters in granites have HCO3-SO4 Na and SO4-HCO3 Na major-ion chemistry, total salinity from 198 to 257 mg/L, pH = 8.6-9.6, silica contents of 19.8 to 24.6 mg/L, and 222Rn activity from 160 to 360 Bq/L (290 Bq/L on average). Judging by their oxygen and hydrogen (deuterium) isotope compositions (-17.5 to -14.2 ‰ and -126.9 to -102.7 ‰, respectively), the Belokurikha aquifers recharge with infiltrating meteoric water, especially the winter precipitation. The carbon isotope composition of dissolved inorganic carbon (-9.7 to -25.6 ‰ δ13СDIC) corresponds to biogenic origin. Comparison of radon-rich mineral waters from different areas of southern Siberia shows that the change from oxidized to reduced environments leads to 232Th/238U increase from 4.20∙10-5-7.39∙10-2 to 0.0022-26, respectively, with an intermediate range of 2.63∙10-5-0.20 in transitional conditions.

Application of Magnetic Force Microscopy for Investigation of Epitaxial Ferro- and Antiferromagnetic Structures.

Growing of epitaxial Fe50Mn50/Fe/Mo/R-sapphire films was performed with a new configuration of two in-plane easy axes of Fe(001)-layer magnetization in which application of annealing in a magnetic field forms an unidirectional anisotropy. The microstructures made from these films exhibited an exchange bias 25-35 G along an exchange field generated at antiferromagnet/ferromagnet (AFM/FM) interface. Magnetic force microscopy (MFM) experiments supported by micromagnetic calculations and magneto-resistive measurements allowed interpretation of the magnetic states of the Fe layer in these microstructures. The magnetic states of the iron layer are influenced more by crystallographic anisotropy of the Fe-layer than by unidirectional exchange anisotropy.