A Rutile Chevron Modulation in Delafossite-Like Ga _3–x In ₃ Ti _x O _9+x/2

Journal Article · Mon May 02 00:00:00 EDT 2016 · Inorganic Chemistry

DOI:https://doi.org/10.1021/acs.inorgchem.6b00147· OSTI ID:1322342

Rickert, Karl; Boullay, Philippe; Malo, Sylvie; Caignaert, Vincent; Poeppelmeier, Kenneth R.

The structure solution of the modulated, delafossite-related, orthorhombic Ga_3–xIn₃Ti_xO_9+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 A_3–xIn₃Ti_xO_9+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 Ga_1.5In₃Ti_1.5O_9.75. 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 Ga_3-xIn₃Ti_xO_9+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 ~3.4 eV before a ~0.4 eV decrease between x = 1.9 and 2.0. After this decrease, stability resumes at ~3.0 eV. Resistance to oxidation and reduction is also presented.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• OSTI ID: 1322342
• Journal Information: Inorganic Chemistry, Vol. 55, Issue 9; ISSN 0020-1669
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY