Band gap narrowing in ferroelectric KNbO3-Bi(Yb,Me)O3 (Me=Fe or Mn) ceramics

PASCUAL-GONZALEZ, Cristina, SCHILEO, Giorgio and FETEIRA, Antonio (2016). Band gap narrowing in ferroelectric KNbO3-Bi(Yb,Me)O3 (Me=Fe or Mn) ceramics. Applied Physics Letters, 109 (13).

Preview	PDF (Replace with published after 12 month embargo) accepted_manuscript.pdf - Accepted Version All rights reserved. Download (1MB) | Preview
	PDF (Acceptance e-mail) Feteira - 13536.pdf - Other Restricted to Repository staff only Download (97kB)

Abstract

The direct optical band gap 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 band gap 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.

Item Type:	Article
Research Institute, Centre or Group - Does NOT include content added after October 2018:	Materials and Engineering Research Institute > Structural Materials and Integrity Research Centre > Centre for Corrosion Technology
Identification Number:	https://doi.org/10.1063/1.4963699
Depositing User:	Antonio Feteira
Date Deposited:	16 Sep 2016 14:27
Last Modified:	18 Mar 2021 07:01
URI:	https://shura.shu.ac.uk/id/eprint/13536

Actions (login required)

View Item

Downloads

Publication Metrics