Reversible crystallization and structural relaxation in amorphous materials used for phase change recording

Project GA ČR 106/11/1152 (2011-2015)

Guarantor: prof. Ing. Jiří Málek, DrSc. (Department of Physical Chemistry)

Member of research team: Ing. Petr Košťál, Ph.D.


The project is focused on a detailed study of reversible crystallization processes as well as the structural relaxation in phase change materials that are used for rewriteable optical or RAM data storage media. Selected compositions of chalcogenide amorphous materials in Ge-Sb-Te and Ge-Sb-Se systems will be prepared. Crystallization processes will be studied by using thermal analysis and various microscopy techniques in combination with some novel methods. A systematic study of thermodynamic properties and viscosity behavior of these compositions will be performed as an integral part of this project. The experimental and theoretical study of structural relaxation in phase change materials is proposed. It will be monitored by volume, enthalpy or entropy change as a function of long term annealing at selected temperatures in the glass transition range. Such a combined approach is useful for searching new materials with tailored properties as well as to better control the reversible crystallization process and to predict the long term stability of amorphous phase. Both aspects are essential for further development of phase change memory devices.