The Ag[Formula: see text]Cu[Formula: text]Se and compounds have been synthesized grown as single crystals. High-temperature X-ray diffraction method was used to study polymorphic transformations. It is shown that the crystals of high-temperature FCC modification are decomposed into Ag 2 Se AgCuSe when temperature decreases below T = 488 K Cu 540 K. Transformations in both reversible. Crystalline parameters obtained dependence lattice for each phase built.

Single crystals of AgCuS, [Formula: see text], text] and compounds were synthesized using the Bridgman method. The crystal structures phase transitions studied by X-ray diffraction (XRD) method in high temperature ranges. monoclinic, orthorhombic, hexagonal cubic phases observed range text]. Thermal expansion coefficients calculated for different according to lattice parameters. It was determined that values thermal differ planes depending on space group symmetry.

Cu2−xTmxSe system was synthesized by partially replacing Cu atoms with Tm and the thermal properties of this were studied. The investigation carried out DSC TGA methods in temperature range T = 30 − 800◦C. It has been established that an increase concentration leads to a decrease value melting temperature. temperatures for mechanism change these compounds at high have determined. Mass loss observed samples during solid-liquid phase transition.

Photoconductivity and photoluminescence of layered FeGaInSe4 crystals at high levels optical excitation have been studied. It has found out that decrease in the lifetime intensities is due to concentration non-equilibrium charge carriers generated by high-power laser radiation. The linear nature lux-ampere characteristic photoconductivity transition from valence band conduction when are excited second harmonic a neodymium laser. may be associated with or radiative trap below bottom band.

The electronic structure and density of states (DOS) BaMnO 3 compound are studied in the framework functional theory (DFT) using generalized gradient approximation (GGA) local (LDA). A number different exchange-correlation functionals including hybrid (PBE, PZ BLYP) exchange techniques have been used. results show that ambient conditions, has metallic structure. It found from DOS calculations overlapping bands near Fermi energy mainly due to 3d state Mn atoms.

In this paper, the results of first principles calculations within framework density functional theory electronic spectrum a GeS crystal are presented. The states and interband optical transitions investigated. It was found that compounds have semiconducting properties with bandgap 1.52 eV. main contribution bands in vicinity Fermi level is from 3[Formula: see text] S Ge atoms, respectively. highest amplitude, about 2.3 eV ([Formula: text], mainly associated between [Formula: text]....

The effect of gamma radiation on the thermodynamic parameters AgCuS compound was studied. Thermodynamic this as Wigner enthalpy, phase transition temperature, free energy were determined by method Differential Thermal Analysis at temperature range T = 600–1250 K. thermal irradiated samples doses D 50 kGy, 100 kGy and 200 showed that dose increases, more is required for transition. This phenomenon explained breaking weak chemical bonds under influence rays formation partial amorphization in...

The mechanism and kinetics of thermal processes in the Ge0.99Nd0.01S compound were studied. parameters studied by Differential Thermal Analysis (DTA) Thermogravimetric (TGA) temperature range 25 0C ≤ T 800 0C. Several transitions observed specified nature these is explained. It was determined that 494 601 0C, a thermoeffect with energy absorption compound. Mass loss 38.84% during this effect phase transition from solid to liquid.

Single crystals of Cu[Formula: see text]Te, text]Zn[Formula: text]Te and text]Cd[Formula: compounds were synthesized by Brijmen method their crystal structure was studied X-ray diffraction. The hexagonal, orthorhombic aand cubic phases these have been determined at room-temperature. Phase transitions high-temperatures observed. Lattice parameters for in the temperature range [Formula: text]–1073 K. From dependences lattice parameters, coefficients thermal expansion existing modifications...

In the presented work, high purity yttrium oxide (99.99%), nanosized crystal density 0.069 g/cm3, specific surface area 100-150 m2/g, average size 8-10 nm and difrent intensities (4.0×10 12 n/cm2, 1.3×10 13 n/cm² 4.0×10 14 n/cm²) in temperature range of 300-700 K, electrical properties were investigated after irradiation with fast neutrons. It has been established that Y 2 O 3 nanocrystals a wide show an increase conductivity according to linear law various intensities. The depending on...

The atomic dynamics and vibrational properties of YbAs2S4 YbAs2Se4 compounds has been studied. studies were carried out by infrared spectroscopy at room temperature in the frequency range ν = 400–2000 cm−1. When analyzing obtained spectra, 8 main maxima observed. As a result analysis, it was found that these correspond to vibrations metal (As) – chalcogen (S,Se) bonds. differences spectra are explained difference ionic radii sulfur selenium atoms divalent state.

In this work, differential scanning calorimetric (DSC) analyses were performed in an Ar inert medium the temperature range of 100–750 K for Y 2 O 3 compound with purity rate 99.99%, density powder form is 0.069 g/cm , specific surface area 100–150 m /g, particle size 8–10 nm irradiated fast neutrons different intensities ([Formula: see text] MeV). Using mathematical approximation methods, equations dependence heat flux function on and capacity after irradiation at over a wide determined. It...

The compound Cu 2 Se has been synthesized and its crystal structure studied. Structural studies were carried out by angle dispersive XRD method. phase transition was detected analyzing the spectra obtained in temperature range [Formula: see text]–1000[Formula: text]K. It found that, under normal conditions, this an orthorhombic structure. At a text][Formula: text]K, occurs from to cubic with formation of highly symmetrical phase. values crystallographic parameters determined for each

AbstractPolymorphic transformations in Rb_0.975Cs_0.025NO_3, Rb_0.950Cs_0.05NO_3, and Rb_0.90Cs_0.1NO_3 crystals grown by us have been studied the X-ray diffraction method. Four different modifications are found for range from room temperature to melting point. The transformation temperatures unit-cell parameters determined of these modifications.