The isothermal sections of the phase diagram of the V–Fe–Sb ternary system have been constructed at 870 and 1070 K by means of X‐ray and electron‐probe microanalyzer (EPMA) analyses over the whole concentration range. The existence of the one ternary phase, VFeSb, with MgAgAs‐ and Ni2In‐type structures was observed at 870 and 1070 K, respectively. The solid solution formed based on the binary Fe2–xSb (Ni2In‐type) compound reaches up to 12 at.‐% of V at 870 K and 40 at.‐% at 1070 K, respectively. Differential scanning calorimetry (DSC) analysis, magnetic susceptibility measurements, and electronic structure calculations showed the absence of a VFeSb polymorph phase transition and indicate that the hexagonal phase is part of the VyFe2–xSb solid solution.

Abstract. For the first time the series of the composites of aniline and natural mineral glauconite with different ratio of components has been synthesized by oxidation of aniline by ammonium peroxydisulfate in 0.5 M citrate acid aqueous solutions in the presence of dispersion of mineral filler. X-ray phase analysis confirms the amorphous-crystalline structure of produced composites.Results of FTIR spectral analysis show that the samples contain PAn in the form of emeraldine salt and also indicate the presence of weak interfacial interaction between particles of glauconite and polyaniline macrochains in the result of the formation of hydrogen bonds. The results of thermogravimetric analysis of synthesized samples with different composition showed that thermal stability of composites samples increases under the higher glauconite content. It is determined that the thermodestruction of composites is a multistage process. The electric conductivity of composites produced samples with high content of polyaniline is on the level of pure polyaniline. The specific magnetization of synthesized composites in applied magnetic field increases to the value which is characteristic of the pure mineral under the increasing of glauconite content in the composite.

The results of a complex study of the semiconductor thermometric material TiСo1-xMnxSb, х=0.01–0.10, for the producing of sensitive elements of thermoelectric and electro resistive sensors are presented. Microprobe analysis of the concentration of atoms on the surface of TiСo1-xMnxSb samples established their correspondence to the initial compositions of the charge, and X-ray phase analysis showed the absence of traces of extraneous phases on their diffractograms. The produced structural studies of the thermometric material TiСo1-xMnxSb allow to speak about the ordering of its crystal structure, and the substitution of Co atoms on Mn at the 4c position generate structural defects of acceptor nature. The obtained results testify to the homogeneity of the samples and their suitability for the study of electrokinetic performances and the manufacture of sensitive elements of thermocouples. Modeling of structural, electrokinetic and energetic performances of TiСo1-xMnxSb, х=0.01–0.10, for different variants of spatial arrangement of atoms is performed. To model energetic and kinetic performances, particularly the behavior of the Fermi level, the band gap, the density of states (DOS) distribution was calculated for an ordered variant of the structure in which Co atoms at position 4c are replaced by Mn atoms. Substitution of Co atoms (3d74s2) by Mn (3d54s2) generates structural defects of acceptor nature in the TiСo1-xMnxSb semiconductor (the Mn atom contains fewer 3d- electrons than Co). This, at the lowest concentrations of impurity atoms Mn, leads to the movement of the Fermi level from the conduction band to the depth of the band gap. In a semiconductor with the composition TiCo0.99Mn0.01Sb, the Fermi level is located in the middle of the band gap, indicating its maximum compensation when the concentrations of ionized acceptors and donors are close. At higher concentrations of impurity Mn atoms, the number of generated acceptors will exceed the concentration of donors, and the concentration of free holes will exceed the concentration of electrons. Under these conditions, the Fermi level approach, and then the level of the valence band TiСo1-xMnxSb cross: the dielectric-metal conductivity transition take place. The presence of a high-temperature activation region on the temperature dependence of the resistivity ln(ρ(1/T)) TiСo1‑xMnxSb at the lowest concentration of impurity atoms Mn, х=001, indicates the location of the Fermi level in the band gap of the semiconductor thermopower coefficient α(Т,х) at these temperatures specify its position - at a distance of ~ 6 meV from the level of the conduction band . In this case, electrons are the main carriers of current. The absence of a low-temperature activation region on this dependence indicates the absence of the jumping mechanism conductivity. Negative values of the thermopower coefficient α(Т,х) TiСo0,99Mn0,01Sb at all temperatures, when according to DOS calculations the concentrations of acceptors and donors are close, and the semiconductor is maximally compensated, can be explained by the higher concentration of uncontrolled donors. However, even at higher concentrations of impurity Mn atoms in TiСo0,98Mn0,02Sb, the sign of the thermopower coefficient α(Т,х) remains negative, but the value of resistivity ρ(х,Т) increases rapidly, and the Fermi level deepens into the forbidden zone at a distance of ~ 30 meV. The rapid increase in the values of the resistivity ρ(х,Т) in the region of concentrations х=0.01–0.02 shows that acceptors are generated in the TiСo1-xMnxSb semiconductor when Co atoms are replaced by Mn, which capture free electrons, reducing their concentration. However, negative values of the thermopower coefficient α(Т,х) are evidence that either the semiconductor has a significant concentration of donors, which is greater than the number of introduced acceptors (х=0.02), or the crystal simultaneously generates defects of acceptor and donor nature. The obtained result does not agree with the calculations of the electronic structure of the TiСo1-xMnxSb semiconductor. It is concluded that more complex structural changes occur in the semiconductor than the linear substitution of Co atoms by Mn, which simultaneously generate structural defects of acceptor and donor nature by different mechanisms, but the concentration of donors exceeds the concentration of generated acceptors. Based on a comprehensive study of the electronic structure, kinetic and energetic performances of the thermosensitive material TiСo1-xMnxSb, it is shown that the introduction of impurity Mn atoms into TiCoSb can simultaneously generate in the semiconductor an acceptor zone (substitution of Co atoms for Mn) and donor zones and of different nature. The ratio of the concentrations of ionized acceptors and donors generated in TiСo1-xMnxSb will determine the position of the Fermi level and the mechanisms of electrical conductivity. However, this issue requires additional research, in particular structural and modeling of the electronic structure of a semiconductor solid solution under different conditions of entry into the structure of impurity Mn atoms. The investigated solid solution TiСo1-xMnxSb is a promising thermometric material.

Polyaniline/glauconite-silica (PАn / Gl-Si) composite were obtained by one-step in situ polymerization of aniline in the presence of microdispersion of natural mineral glauconite-silica. The physicochemical properties (phase content, thermal stability, conductivity and magnetization) of the produced samples of composites with different ratio of components have been studied. It was shown that the polymeric component stipulates the conductivity for the synthesized composite samples, while the mineral particles stipulate their magnetic properties and higher thermal stability in comparison with individual polyaniline. Besides, it was determined that participation of the surface of glauconite-silica microparticles in the process of aniline polymerization leads to considerable increasing of ordering of the polymer in the composite.

The peculiarities of electronic and crystal structures of Zr1-xVxNiSn (x = 0 - 0.10) semiconductive solid solution were investigated. To predict Fermi level εF behavior, band gap εg and electrokinetic characteristics of Zr1-xVxNiSn, the distribution of density of electronic states (DOS) was calculated. The mechanism of simultaneous generation of structural defects of donor and acceptor nature was determined based on the results of calculations of electronic structure and measurement of electrical properties of Zr1-xVxNiSn semiconductive solid solution. It was established that in the band gap of Zr1-xVxNiSn the energy states of the impurity donor εD2 and acceptor εA1 levels (donor-acceptor pairs) appear, which determine the mechanisms of conduction of semiconductor.