The importance of complexing in controlling the solubility, transport and precipitation of ore metals in aqueous solutions is a recurrent theme of this book. In this chapter experimental results obtained at the Institute of the Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry of the Russian Academy of Sciences, Moscow during the past ten years are reviewed. The results presented here, on the solubility and complexing of a disparate range of metals in aqueous solutions, are linked together by a common methodological approach: the investigation, where possible, of simple systems to determine equilibrium constants for specific complex formation. The scope of this paper is unashamedly idiosyncratic. Some elements have received detailed and extensive study, others only limited investigation. However, the authors attempt to describe the results of many years work to characterize some Fluids in the Crust: Equilibrium and transport properties.

We investigate the nature of transport and ferromagnetic properties of the epitaxial GaAs structure with the Mn δdoped layer. To modify the properties of the structure electrically active radiation defects are created by irradiation with 50 keV helium ions and a fluence in the range of 1 × 10 11 -1 × 10 13 cm -2 . The investigations show that transport properties of the structure are determined by two parallel conduction channels (the channel associated with hole transport in a valence band and the channel associated with electron transport in the Mn-related impurity band) and that ferromagnetic properties are determined by electrons localized at allowed states within the Mn impurity band. The ferromagnetic properties of the Mn δ-layer region cannot be affected by the closely located InGaAs quantum well, since the presence of quantum well has negligible influence on the Mn impurity band filling by electrons.

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The influence of He + ion irradiation on the transport and magnetic properties of epitaxial layers of a diluted magnetic semiconductor (DMS) (In,Fe)Sb, a two-phase (In,Fe)Sb composite and a nominally undoped InSb semiconductor has been investigated. In all layers, a conductivity type conversion from the initial n-type to the ptype has been found. The ion fluence at which the conversion occurs depends on the Fe concentration in the InSb matrix. Magnetotransport properties of the two-phase (In,Fe)Sb layer are strongly affected by ferromagnetic Fe inclusions. An influence of the number of electrically active radiation defects on the magnetic properties of the single-phase In 0.75 Fe 0.25 Sb DMS has been found. At the same time, the results show that the magnetic properties of the In 0.75 Fe 0.25 Sb DMS are quite resistant to significant changes of the charge carrier concentration and the Fermi level position. The results confirm a weak interrelation between the ferromagnetism and the charge carrier concentration in (In,Fe)Sb.

Продемонстрирована возможность изменения типа магнитной структуры многослойных пленок CoPt под влиянием магнитного поля зонда атомно-силового микроскопа. Предложен новый метод бесконтактного проведения магнитно-силовых измерений, основанный на искусственном увеличении электростатического взаимодействия зонда и образца. Данный метод позволяет контролируемым образом менять расстояние между зондом и пленкой, регулируя силу магнитного взаимодействия. Используя его, можно из однородно намагниченного состояния создать как лабиринтную доменную структуру, так и изолированные домены, являющиеся, по-видимому, магнитными скирмионами. Работа выполнена в рамках реализации государственного задания-проект № 8.1751.2017/ПЧ Минобрнауки России и при поддержке РФФИ (гранты 16-07-01102_а и № 17-37-80008_мол_эв_а).