|
Title
|
|
|
|
: a modulated scheelite-type structure and conductivity properties
| |
|
Author
|
|
|
|
| |
|
Abstract
|
|
|
|
| Scheelite-type compounds with the general formula (A1,A2)n[(B1,B2)O4]m (2/3 ≤ n/m ≤ 3/2) are the subject of large interest owing to their stability, relatively simple preparation, and optical properties. The creation of cation vacancies (□) in the scheelite-type framework and the ordering of A cations and vacancies can be a new factor in controlling the scheelite-type structure and properties. For a long time, cation-deficient Nd3+:M2/7Gd4/7□1/7MoO4 (M = Li, Na) compounds were considered as potential lasers with diode pumping. They have a defect scheelite-type 3D structure (space group I41/a) with a random distribution of Li+(Na+), Gd3+, and vacancies in the crystal. A Na2/7Gd4/7MoO4 single crystal with scheelite-type structure has been grown by the Czochralski method. Transmission electron microscopy revealed that Na2/7Gd4/7MoO4 has a (3 + 2)D incommensurately modulated structure. The (3 + 2)D incommensurately modulated scheelite-type cation-deficient structure of Na2/7Gd4/7MoO4 [super space group I4̅ (αβ0,βα0)00] has been solved from single-crystal diffraction data. The solution of the (3 + 2)D incommensurately modulated structure revealed the partially disordered distribution of vacancies and Na and Gd cations. High-temperature conductivity measurements performed along the [100] and [001] orientation of the single crystal revealed that the conductivity of Na2/7Gd4/7MoO4 at T = 973 K equals σ = 1.13 × 105 Ω1 cm1. |
| |
|
Language
|
|
|
|
English
| |
|
Source (journal)
|
|
|
|
Inorganic chemistry / American Chemical Society. - Easton, Pa
| |
|
Publication
|
|
|
|
Easton, Pa
:
2012
| |
|
ISSN
|
|
|
|
0020-1669
| |
|
DOI
|
|
|
|
10.1021/IC300221M
| |
|
Volume/pages
|
|
|
|
51
:9
(2012)
, p. 5313-5324
| |
|
ISI
|
|
|
|
000303952900055
| |
|
Full text (Publisher's DOI)
|
|
|
|
| |
|
Full text (publisher's version - intranet only)
|
|
|
|
| |
|