A Rutile Chevron Modulation in Delafossite-Like Ga3-xIn3TixO9+x/2.
Inorg Chem
; 55(9): 4403-9, 2016 05 02.
Article
em En
| MEDLINE
| ID: mdl-27089247
ABSTRACT
The structure solution of the modulated, delafossite-related, orthorhombic Ga3-xIn3TixO9+x/2 for x = 1.5 is reported here in conjunction with a model describing the modulation as a function of x for the entire system. Previously reported structures in the related A3-xIn3TixO9+x/2 (A = Al, Cr, or Fe) systems use X-ray diffraction to determine that the anion lattice is the source of modulation. Neutron diffraction, with its enhanced sensitivity to light atoms, offers a route to solving the modulation and is used here, in combination with precession electron diffraction tomography (PEDT), to solve the structure of Ga1.5In3Ti1.5O9.75. We construct a model that describes the anion modulation through the formation of rutile chevrons as a function of x. This model accommodates the orthorhombic phase (1.5 ≤ x ≤ 2.1) in the Ga3-xIn3TixO9+x/2 system, which transitions to a biphasic mixture (2.2 ≤ x ≤ 2.3) with a monoclinic, delafossite-related phase (2.4 ≤ x ≤ 2.5). The optical band gaps of this system are determined, and are stable at â¼3.4 eV before a â¼0.4 eV decrease between x = 1.9 and 2.0. After this decrease, stability resumes at â¼3.0 eV. Resistance to oxidation and reduction is also presented.
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01-internacional
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MEDLINE
Idioma:
En
Revista:
Inorg Chem
Ano de publicação:
2016
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Article