A Rutile Chevron Modulation in Delafossite-Like Ga_3–xIn₃Ti_xO_9+x/2

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 ∼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.

3D Electron Diffraction: The Nanocrystallography Revolution

“…3D ED is an extremely promising technique for the structure determination of functional layered oxides, even if characterized by disorder , or incommensurate modulations. ,,, 3D ED was also used for the analysis of structure modifications caused by the thermal annealing of Ni/Au electrodes, and for the study of materials engineered for electrochemical applications. ,, In this regard, Karakulina et al . performed the first in situ charge/discharge experiment on a (Li)­FePO 4 electrode.…”

Stairlike Aurivillius Phases in the Pseudobinary Bi5Nb3O15–ABi2Nb2O9 (A = Ba and Sr) System: A Comprehensive Analysis Using Superspace Group Formalism

“…PEDT data sets were analyzed using the computer programs PETS , SUPERFLIP , and JANA2006 following a procedure resembling the one used in single-crystal X-ray diffraction. Details about the methodology to solve complex structures such as incommensurately modulated structures using PEDT can be found elsewhere. − For each data set, the result is a list of hklm indices with associated intensities and estimated standard deviations based on counting statistics.…”

Exotic Compositional Ordering in Manganese–Nickel–Arsenic (Mn‐Ni‐As) Intermetallics

“…The PEDT data set was analyzed using the computer programs PETS2.0 12 , SUPERFLIP 13 , and JANA2006. 14 Details about the methodology to solve incommensurately modulated structures using PEDT can be found elsewhere [15][16][17][18] . For each data set, the result is a list of hklm indices with associated intensities and estimated standard deviations based on counting statistics (Table 1).…”