Crystal structure, dielectric properties, and optical bandgap control in KNbO 3 –BiMnO 3 ceramics

PASCUAL‐GONZALEZ, Cristina, ELICKER, Carolina, MOREIRA, Mario L., CAVA, Sergio, STERIANOU, Iasmi, WANG, Dawei and FETEIRA, Antonio (2022). Crystal structure, dielectric properties, and optical bandgap control in KNbO 3 –BiMnO 3 ceramics. Journal of the American Ceramic Society.

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Abstract: (1 − x)KNbO3–xBiMnO3 (0 ≤ x ≤ 0.25) ceramics were prepared by the solid‐state reaction method. An X‐ray diffraction analysis combined with Raman spectroscopy showed the co‐solubility of Bi and Mn in the orthorhombic structure to be less than 5% BiMnO3. Orthorhombic and pseudocubic symmetries coexist in the 0.05 ≤ x ≤ 0.15 region, coinciding with a bimodal grain size distribution. This coexistence of crystal symmetries is further corroborated by several anomalies in the dielectric behavior, which can be ascribed to structural phase transitions. For x ≥ 0.20, only one dielectric anomaly is detected around 100°C, which is commensurate with in situ Raman spectroscopy analysis. This work also shows that Bi/Mn co‐doping can be employed to tailor the bandgap of KNbO3, which narrows continuously with increasing x, resulting in ∼1‐eV narrowing for single‐phase x = 0.25. This may offer the possibility to employ this ferroic material in photoresponsive technologies.

Item Type: Article
Additional Information: ** Article version: VoR ** From Wiley via Jisc Publications Router ** Licence for VoR version of this article: **Journal IDs: issn 0002-7820; issn 1551-2916 **Article IDs: publisher-id: jace18779 **History: published 26-09-2022; accepted 09-08-2022; rev-recd 04-08-2022; submitted 10-01-2022
Uncontrolled Keywords: SPECIAL ISSUE ARTICLE, SPECIAL ISSUE ARTICLES, ferroelectricity/ferroelectric materials, Raman spectroscopy, solid solutions
Identification Number:
SWORD Depositor: Colin Knott
Depositing User: Colin Knott
Date Deposited: 29 Sep 2022 08:39
Last Modified: 12 Oct 2023 10:01

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