Local structures around the substituted elements in mixed layered oxides

Shota Akama; Wataru Kobayashi; Kaoru Amaha; Hideharu Niwa; Hiroaki Nitani; Yutaka Moritomo

doi:10.1038/srep43791

Local structures around the substituted elements in mixed layered oxides

Sci Rep. 2017 Mar 2:7:43791. doi: 10.1038/srep43791.

Authors

Shota Akama¹, Wataru Kobayashi^{1

2

3

4}, Kaoru Amaha¹, Hideharu Niwa^{1

2

3}, Hiroaki Nitani⁵, Yutaka Moritomo^{1

2

3

4}

Affiliations

¹ Graduate School of Pure and Applied Science, University of Tsukuba, Tsukuba 305-8571, Japan.
² Faculty of Pure and Applied Science, University of Tsukuba, Tsukuba 305-8571, Japan.
³ Tsukuba Research Center for Interdisciplinary Materials Sciences (TIMS), University of Tsukuba, Tsukuba 305-8571, Japan.
⁴ Center for Integrated Research in Fundamental Science and Engineering (CiRfSE), University Tsukuba, Tsukuba 305-8571, Japan.
⁵ Institute of Materials Science, High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan.

Abstract

The chemical substitution of a transition metal (M) is an effective method to improve the functionality of a material, such as its electrochemical, magnetic, and dielectric properties. The substitution, however, causes local lattice distortion because the difference in the ionic radius (r) modifies the local interatomic distances. Here, we systematically investigated the local structures in the pure (x = 0.0) and mixed (x = 0.05 or 0.1) layered oxides, Na(M_1-xM'_x)O₂ (M and M' are the majority and minority transition metals, respectively), by means of extended X-ray absorption fine structure (EXAFS) analysis. We found that the local interatomic distance (d_M-O) around the minority element approaches that around the majority element to reduces the local lattice distortion. We further found that the valence of the minority Mn changes so that its ionic radius approaches that of the majority M.

Publication types

Research Support, Non-U.S. Gov't