Role of non-stoichiometry in the cracking of oxide crystals

• Published in: Journal of crystal growth Vol. 310; no. 11; pp. 2899 - 2905
• Main Authors: Sangeeta, Sabharwal, S.C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.05.2008; Elsevier
• Subjects: A1. Solidification; A2. Growth from melt; B1. Oxides; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Growth from melts; zone melting and refining; Materials science; Methods of crystal growth; physics of crystal growth; Physics; Thermal expansion; thermomechanical effects and density; Thermal properties of condensed matter; Thermal properties of crystalline solids; 81.10; A1. Solidification; B1. Oxides; A2. Growth from melt; Crystal growth; Stoichiometry; Lead tungstates; Property composition relationship; Cracking; Mechanical properties; Heat treatments; Thermal stability; Solidification; Monocrystals; Growth from melt
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2008.01.048

The cracking and stoichiometric deviations frequently observed in crystals of mixed oxides have generally been perceived to be unrelated phenomena. The present study pertains to the cracking in Czochralski grown crystals of three different materials, viz. CdWO 4, PbWO 4 and ZnWO 4. The results obtained on the single-crystal growth as well as on the thermal stability of melts of these materials and of their constituent oxides demonstrate, for the first time, that stoichiometric deviations manifest as cracks in the crystals. An important outcome of this investigation is that materials exhibiting a small degree of super-cooling with stable melting and solidification temperatures should be less prone to cracking.