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Title: Raman Study of the Structural Distortion in the Ni 1–xCo xTiO 3 Solid Solution

In this paper, Raman spectra were collected on Ni 1–xCo xTiO 3 (0 ≤ x ≤ 1) ilmenite samples as a function of the temperature between 4 and 1200 K. An evident symmetry lowering from the prototype R$$\bar{3}$$symmetry is observed. The distortion was largest for the x = 0.40 and 0.50 samples and significantly diminished for small and large values of x. The distortion was preserved in the whole temperature range and, except for the x = 0.50 sample, did not show significant changes. Notably, between 25 and 69 K, distortion of the x = 0.40 sample is accompanied by ferromagnetic order. The direct cation–cation and O-mediated indirect interactions are discussed as mechanisms behind the distortion and magnetic order. A reversible order–disorder phase transformation, assigned to occur between the ilmenite and corundum phases, took place at 973 K in the x = 0.50 sample. Completion of the transformation took over 1 h. Finally, the role of the overlap of Co/Ni and Ti 3d orbitals through O octahedral faces for charge transfer is discussed.
Authors:
 [1] ;  [1] ;  [2] ;  [3]
  1. Finnish Research and Engineering, Helsinki (Finland)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Volume: 55; Journal Issue: 18; Journal ID: ISSN 0020-1669
Publisher:
American Chemical Society (ACS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Contributing Orgs:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Finnish Research and Engineering, Helsinki (Finland)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1343526