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Comparison of defect processes in RE A l O 3 perovskites and RE 3 A l 5 O 12 garnets
Author(s) -
Patel Ankoor P.,
Stanek Chris R.,
Grimes Robin W.
Publication year - 2013
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201248583
Subject(s) - stoichiometry , yttrium , lattice (music) , crystallography , ionic radius , chemistry , trapping , materials science , physics , ion , oxide , organic chemistry , acoustics , ecology , biology
Defects can decrease the efficiency of scintillators by trapping electrons. Here, point defects in RE AlO 3 and RE 3 Al 5 O 12 are predicted with pair potential simulations, where RE is yttrium or a trivalent rare earth cation. It was found that RE AlO 3 shows a preference for Al 2 O 3 ‐excess whereas RE 3 Al 5 O 12 most readily exhibits RE 2 O 3 ‐excess. Also, lattice volume changes for the energetically favorable intrinsic mechanisms are relatively invariant as a function of RE cation size in RE 3 Al 5 O 12 , but not in RE AlO 3 . However, in non‐stoichiometric RE 3 Al 5 O 12 , the energetically preferred disorder mechanism results in an increasing lattice expansion with increasing RE radius whereas, in non‐stoichiometric perovskites, a relatively small, radius independent, lattice contraction is predicted. These results illustrate that defect behavior in RE AlO 3 perovskites and RE 3 Al 5 O 12 garnets is quite disimilar.