Crystal growth of nonstoichiometric compoundsстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:A key issue in materials research is the preparation of crystals of inorganic compounds with predetermined composition, structure, and, hence, properties. In connection with this, this paper scrutinizes the concepts of stoichiometry, nonstoichiometry, and deviation from stoichiometry and the use of phase diagrams in selecting conditions for the crystal growth of nonstoichiometric compounds. Since nonstoichiometry is associated with structural defects, attention is also paid to defect classification and formation. The behavior of defects in crystals of oxides, chalcogenides, carbides, and other compounds of transition metals ranges from the point-defect regime, controlled by entropy, to the enthalpy-controlled regime. To develop an appropriate theory of nonstoichiometric compounds, it is then necessary to address crystal-chemical and thermodynamic issues. This paper is also concerned with the defect structure of highly imperfect crystals of nonstoichiometric compounds with a broad homogeneity range: the concepts of defect and structural transition due to defect interactions and temperature effect. The thermodynamic aspect of the problem includes criteria for evaluating the stability of imperfect nonstoichiometric crystals. We also consider the specifics of the concepts of existing, stable, and metastable phases, spinodal decomposition conditions, and issues associated with phase equilibria in homologous series of compounds with narrow homogeneity ranges. The paper also deals with synthesis methods, nonstoichiometry control, and criteria for evaluating the homogeneity of nonstoichiometric crystals.