Dang, Y., Phuah, X.L., Wang, H. et al. (3 more authors) (2021) Electrical properties and charge compensation mechanisms of Cr-doped rutile, TiO2. Physical Chemistry Chemical Physics, 23 (38). pp. 22133-22146. ISSN 1463-9076
Abstract
Cr-doped rutile, Ti1−xCrxO2−x/2−δ, powders and ceramics with 0 ≤ x ≤ 0.05 were prepared by solid state reaction and sintered at 1350 °C. Cr distribution is homogeneous with no evidence of either segregation or crystallographic shear plane formation. For high x compositions, >∼0.01, Cr substitution is charge-compensated ionically by oxygen vacancies with two Cr3+ ions for each vacancy and the materials are electronically insulating. For low x compositions, the materials are semiconducting. This is attributed to a new charge compensation mechanism involving Ti3+ ions created in response to the local electroneutrality requirement for two trivalent cations to be in close proximity to each oxygen vacancy. At very low dopant concentrations, ≪0.01, the dopants are well-separated and instead, some Ti3+ ions act as a second dopant to preserve local electroneutrality. For intermediate x compositions, a core–shell structure is proposed consisting of semiconducting grain interiors containing Ti3+ ions surrounded by a more insulating shell with Cr3+ ions as the only acceptor dopant. Lattice parameters show unusual, non-linear Vegard's law behaviour characterised by a maximum in cell volume at intermediate x ∼ 0.005, that is attributed to the composition-dependent presence of Ti3+ ions.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © 2021 the Owner Societies. This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence (http://creativecommons.org/licenses/by-nc/3.0/). |
Dates: |
|
Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Materials Science and Engineering (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 19 Nov 2021 09:10 |
Last Modified: | 19 Nov 2021 09:10 |
Status: | Published |
Publisher: | Royal Society of Chemistry (RSC) |
Refereed: | Yes |
Identification Number: | 10.1039/d1cp01735g |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:180637 |