Paramagnetic layered semiconductor NbS₂ doped with some transition metals can transform into ferromagnetic material. That is why such materials are promising candidates for spintronic devices. It is found that only at certain concentrations of a doping metal T crystallographic ordering is possible, which is essential for magnetic ordering of ternary compounds TNbS₂. In particular, CrNb3S6 crystals are studied, which form almost completely ordered superstructure with intercalated Cr between NbS₂ layers. The main difficulty in crystal growth is reaching stoichiometry of the compound. This problem is solved in the developed method of two-staged gas transport chemical reaction. This new approach provides growth of CrNb₃S₆ single crystals of several millimeters in diameter and 0.3–0.5 mm thickness. X-ray phase analysis (XRD) of powders is performed to identify all phases involved in synthesis and growth of the crystals. High frequency absorption in external periodic magnetic field as a function of temperature and intensity of magnetic field is used to estimate the temperature of ferromagnetic transition in CrNb₃S₆ single crystals. The Curie temperature is estimated as 115 K. Growth of CrNb₃S₆ crystals from vapor phase is studied in detail and full analysis of phase transitions during growth is given. It has been shown that using of high frequency absorption in the crystal provides reliable estimation of the point of ferromagnetic transition in this semiconductor. The authors are grateful to the Physical Science Department of Russian Academy of Sciences for financial support of the studies in the frameworks of the program “Physics of new materials and structures” (project no. 00-12-10).

Vertical zone melting under argon pressure is used to grow crystals of GaSe and GaS binary compounds, as well as solid solutions in the GaSe–GaS system. The crystals of these compounds are applied in...

Room-temperature recrystallization of KCl single crystals, both pure and doped with 0.02 and 0.06 wt % Sr, deformed preliminarily at 250°C is studied. It is found that annealing of the original single crystals at 650°C results in the precipitation of the SrCl₂ phase from the solid solution. X-ray diffraction studies reveal that the deformed crystals undergo ageing at room temperature, which is accompanied by a change in the phase composition. In the first place, particles of the KSr₂Cl₅ phase are formed instead of the phase SrCl₂ observed in the original and deformed crystals. These particles, which are located at the boundaries of growing recrystallized grains (twins of the original single crystal) occupying not more than 8% of the volume, impede the motion of grain boundaries and hamper further recrystallization. Second, it is shown that post-deformation ageing occurring in the remaining 92% of the deformed crystal region that has not undergone recrystallization lends stability to the strain-hardened state of alkali halide crystals over a period of at least two years at room temperature.

Spatial localization of deformation bands in LiF and KCl single crystals caused by instability of plastic flow in the strain rate range from 5 × 10⁻⁶ to 2 × 10⁻⁴ s⁻¹ was studied experimentally. The geometrical parameters of localized shift bands (LSB) were studied as a function of strain rate and temperature. To study the LSB relief, a surface profilometry technique was used for the first time, which made it possible to determine the LSB parameters at the early stages of plastic flow (for strains in the range from 0.5 to 2%). The formation and branching of LSB steps on the surface of a deformed crystal due to the generation and motion of dislocations were found to be scaled. It was shown experimentally that the LSB formation is a thermally activated process that occurs through dislocation glide and is limited by dislocation creep.