Pascual-Gonzalez, C., Schileo, G. and Feteira, A. (2016) Band gap narrowing in ferroelectric KNbO 3 -Bi(Yb,Me)O3 (Me=Fe or Mn) ceramics. Applied Physics Letters, 109 (13). 132902. ISSN 0003-6951
Abstract
The direct optical bandgap in ferroelectric KNbO3-Bi(Yb,Me)O3 (Me = Fe or Mn) ceramics fabricated by the solid state reaction method varies from 3.2 eV for KNbO3 down to 2.2 eV for 0.95KNbO3-0.05BiYbO3, as revealed by optical spectroscopic ellipsometry. This narrowing of bandgap is accompanied by an apparent increase of the room-temperature relative permittivity from 320 for KNbO3 to 900 for 0.95KNbO3-0.05BiYbO3. All compositions studied exhibit dielectric anomalies associated with structural phase transitions, and their ferroelectric nature is corroborated by the presence of a sharp mixed mode (at ∼190 cm−1) and by a Fano-type resonant dip in their Raman spectra.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016 AIP Publishing. Reproduced in accordance with the publisher's self-archiving policy. |
Dates: |
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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: | 29 Sep 2017 12:41 |
Last Modified: | 28 Sep 2018 00:38 |
Published Version: | https://doi.org/10.1063/1.4963699 |
Status: | Published |
Publisher: | AIP Publishing |
Refereed: | Yes |
Identification Number: | 10.1063/1.4963699 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:121811 |