Chalcogenide glasses of the Se-S system (0-10 at % S) crystallized under the influence of a cav itating ultrasonic field at temperatures of 65 and 73°C. The process was evaluated with respect to spectra of optical transmission in the interval of 400-5000 cm -1 . Layer by layer removal of the surface of a sample with subsequent evaluation of its transparence was performed for assessment of the heterogeneity of crystalliza tion. It is shown that the crystallization sharply intensifies under the simultaneous impact of temperature and a variable field of elastic stresses, in comparison with the crystallization under their separate action. Optical effects exhibit nonlinearity by glass composition and an anisotropy concerning the position of a US source. A complicated hierarchical pattern of the nucleation stage is shown by electron microscopy. The results are construed in the context of the synergetic approach, and hypervalent bonds based on S.A. Dembovskii are viewed as a microscopic base of self organization.

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Phase transformations in (GeTe)m(Sb2Te3)n (m: n = 1:1; 1:2; 2:1) alloys and thin films on their basis were studied during thermal cycling by differential scanning calorimetry, and some thermal properties were determined. Exothermal peaks due to the amorphous → crystalline phase changes were observed in all thin films. In addition, reproducible endothermic peak in the range of 390‐415 °C was revealed in thin films as well as in bulk Ge2Sb2Te5, GeSb2Te4, GeSb4Te7 samples, which may influence on the kinetics and endurance of data reading processes in phase‐change memory devices. Activation energies of observed heat effects were estimated with using Kissinger's method, and nature of the given endothermic peak was discussed. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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