Features of the crystal structure and electrical properties of sodium chloride at pressure 20-50 GPa

The electrical properties of polycrystalline samples of sodium chloride are studied at direct and alternating current in a wide range of frequencies at high pressure and room temperature. Graphic analysis of the experimental data [1-3] in the view of equivalent circuits allowed us to separate the contributions to conductivity caused by grains and intergrain boundaries. Features of impedance at pressure up to 37 GPa are in good agreement with earlier data and structural changes. It is shown that in the studied materials the electrical resistance of grains is much greater than the resistance of intergrain boundaries. © 2013 Allerton Press, Inc

Phase equilibria and thermodynamic properties of oxide systems on the basis of rare earth, alkaline earth and 3d-transition (Mn, Fe, Co) metals. A short overview of

Review is dedicated studies of phase equilibria in the systems based on rare earth elements and 3d transition metals. It’s highlighted several structural families of these compounds and is shown that many were found interesting properties for practical application, such as high conductivity up to the superconducting state, magnetic properties, catalytic activity of the processes of afterburning of exhaust gases, the high mobility in the oxygen sublattice and more

Phase equilibria, crystal structure and oxygen nonstoichiometry of the complex oxides in Sm – (Sr, Ba) – (Co, Fe) – O systems

Received: 18.01.2018. Accepted: 14.02.2018. Published: 10.05.2018.Present paper contains available information on the phase equilibria in the Sm – (Sr, Ba) – (Co, Fe) – O systems, including the synthesis routes used, crystal structure, which is often depended on oxygen nonstoichiometry, the data on thermodynamic stability of complex oxides, the obtained results on the homogeneity ranges of solid solutions, formed in the systems, and graphical presentation of phase relations in a form of phase diagrams

Effect of high pressure on the thermoelectrical properties of single-walled and double-walled carbon nanotubes

The effect of high pressure on the Seebeck coefficient and temperature dependences of the electrical resistance of single-wall and double-walled carbon nanotubes was studied in order to detect phase transformations occurring in carbon nanotubes in the pressure range 4-46 GPa. Diamond anvil cells with conductive synthetic diamonds were used to create high pressures. We observed a number of features associated with the structure changes of nanotubes. Temperature dependences of the electrical resistance of single and double-walled carbon nanotubes have the form characteristic of nondegenerate semiconductors. Analysis of results indicates the destruction of the structure of carbon nanotubes at high pressure. © Published under licence by IOP Publishing Ltd

Crystal structure and properties of novel oxide Sm0.9Ca1.1Fe0.7Co0.3O4–δ

Received: 13.11.2018. Accepted: 05.12.2018. Published: 31.12.2018.Sm0.9Ca1.1Fe0.7Co0.3O4–δ oxide with the K2NiF4‑type structure was prepared using a glycerin-nitrate technique. The XRD pattern of Sm0.9Ca1.1Fe0.7Co0.3O4–δ was refined by the Rietveld method within an orthorhombic structure (space group Bmab). The electrical conductivity, Seebeck coefficient, and thermal expansion of Sm0.9Ca1.1Fe0.7Co0.3O4–δ were measured depending on temperature in air. The change of oxygen nonstoichiometry determined by TGA in air does not exceed 0.01. The oxygen content in Sm0.9Ca1.1Fe0.7Co0.3O4–δ determined by the reduction in a hydrogen flux is equal to 3.96 ± 0.01. The positive value of Seebeck coefficient indicates that the predominant charge carriers in the oxide studied are electron holes.This work was supported in parts by Act 211 Government of the Russian Federation, agreement 02.A03.21.0006