M. G. Kakazey, G. N. Kakazei, J. G. Gonzalez-Rodriguez: Mechanothermal Effects on the Defect Structure in ZnO Powders Subjected to Hydrostatic Pressure

Crystal Research and Technology

Cryst. Res. Technol. 36 (2001) 429 - Abstract -

M. G. Kakazey, G. N. Kakazei*, J. G. Gonzalez-Rodriguez**

Institute for the Problems of Materials Science of the National Academy of Science of the Ukraine
*Institute of the Magnetism of the National Academy of Science of the Ukraine
**Centro de Investigaciones en Ingenieria y Ciencias Aplicadas, Cuernavaca, Mexico

Mechanothermal Effects on the Defect Structure in ZnO Powders Subjected to Hydrostatic Pressure

Using electron paramagnetic resonance (EPR) spectroscopy method the mechanism of defect formation has been studied in ZnO powders, put to a bottoming (a hydrostatic pressing) up to P=8 GPa. The initiation of 6 paramagnetic centers by a pressing has been shown SDS (shallow donor states) - V and SDS_imp (SDS associated with impurities) - VI). The dependence of the signal intensity (I) on pressure P has been studied. The maxima on curves I =f (P) for EPR signals from centres I and II are attributed to the development of mechanothermal processes promoting an annealing of the created defects during pressing. Comparison with the data on annealing of paramagnetic centers has allowed to construct the dependence of an average sample temperature as a function of hydrostatic pressure, and to propose the model diagram of the development of mechanothermal processes under pressure.

Keywords: defects, pressing, deformation, fracture, zinc-oxide, powders, mechanothermal processes, EPR

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