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Mechanothermal Effects on the Defect Structure in ZnO Powders Subjected to Hydrostatic Pressure
Author(s) -
Kakazey M.G.,
Kakazei G.N.,
GonzalezRodriguez J.G.
Publication year - 2001
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/1521-4079(200106)36:4/5<429::aid-crat429>3.0.co;2-m
Subject(s) - electron paramagnetic resonance , hydrostatic pressure , annealing (glass) , paramagnetism , impurity , pressing , hydrostatic equilibrium , materials science , chemistry , condensed matter physics , analytical chemistry (journal) , crystallography , nuclear magnetic resonance , composite material , thermodynamics , physics , organic chemistry , quantum mechanics , chromatography
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 ( $V^-_{Zn} : Zn^o_i - {\bf I}, \, V^-_{Zn} - {\bf II}, \, (V^-_{Zn})^-_2 - {\bf III}, \, {\bf V} ^+_{{\bf o}} - {\bf IV}$ , 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.