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Investigation of structural transformations in Cu 2 Se
Author(s) -
Asadov Yu. G.,
Jabrailova G. A.
Publication year - 1973
Publication title -
kristall und technik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0023-4753
DOI - 10.1002/crat.19730080413
Subject(s) - inverse , diffraction , transformation (genetics) , crystallography , reflection (computer programming) , debye , multiplicity (mathematics) , materials science , chemistry , mathematics , geometry , physics , optics , condensed matter physics , computer science , biochemistry , gene , programming language
Structural transformations in Cu 2 Se have been studied by the method of hightemperature roentgenography. From a diffraction record of reflection angles and from a Debye‐powder pattern the unit‐cell parameters of a rhombic α‐modification have been calculated at temperatures of 25, 50, 100, and 132 °C. Using the diffraction line (027) disappearing under the α → β transformation and appearing again in the course of the inverse β → α transformation it has been found that the equilibrium temperature between the α‐ and β‐modifications is T 0 = 134 ± 0.5 °C. The unit cell parameter of a hightemperature face‐centered cubic β‐modification at temperatures of 150, 200, 250, and 300 °C also has been determined. In the course of mutual transformations a rigid orientational linkage has been found to exist between the α‐ and β‐modifications. It has been discovered that when the multiplicity of α → β and β → α transformations n reaches a value of approximately 30, a β‐Cu 2 Se → Cu 2 – x Se transformation (where x = 0.20) takes place which is not followed by an inverse transformation.