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Atomistic Modeling of Native Point Defects in Yttrium Aluminum Garnet Crystals
Author(s) -
Kuklja Maija M.,
Pandey Ravindra
Publication year - 1999
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1999.tb02172.x
Subject(s) - yttrium , materials science , crystallographic defect , yttrium aluminium garnet , aluminium , lattice (music) , lattice constant , ion , extended x ray absorption fine structure , dielectric , atom (system on chip) , crystal structure , condensed matter physics , molecular physics , crystallography , absorption spectroscopy , doping , chemistry , optics , metallurgy , physics , diffraction , embedded system , oxide , optoelectronics , organic chemistry , computer science , acoustics
Native point defects in yttrium aluminum garnet (YAG) are studied in the framework of the pair‐potential approximation, coupled with the shell‐model description of the lattice ions. For the perfect lattice, a new set of potential parameters is obtained; these parameters reproduce the structure, elastic, and dielectric constants of YAG very well. The calculated formulation energies for native defects suggest that antisite disorder is preferred over Frenkel and Schottky‐like disorder in YAG. The calculated values of the distortion that is caused by the antisite Y atom that substitutes in the Al site in the lattice are in excellent agreement with the extended X‐ray absorption fine‐structure (EXAFS) measurements. In nonstoichiometric YAG, the calculated reaction energies indicate that excess Y 2 O 3 or Al 2 O 3 most likely is accommodated by the formation of antisites, rather than vacancies, in the lattice.