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Title: Softening of infrared-active mode of perovskite BaZrO{sub 3} proved by terahertz time-domain spectroscopy

Abstract

The low-frequency infrared-active optical modes were studied in a barium zirconate, BaZrO{sub 3}, single crystal with the perovskite structure using terahertz (THz) time-domain spectroscopy (TDS). The real and imaginary parts of the dielectric constants were accurately determined in the frequency range between 0.2 and 2.7 THz. Upon cooling from room temperature to 8 K, the lowest-frequency TO1 mode at 2.32 THz showed a pronounced softening to 1.94 THz. The real part of the dielectric constant at 0.5 THz determined by THz-TDS obeys Barrett's relation, and the existence of a plateau confirms that the quantum effects lead to saturation of the soft mode frequencies of the TO1 and TO2 modes below ≈20 K. This is reminiscent of incipient ferroelectrics with the perovskite structure such as CaTiO{sub 3}.

Authors:
; ;  [1]
  1. Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan)
Publication Date:
OSTI Identifier:
22399011
Resource Type:
Journal Article
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 106; Journal Issue: 18; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0003-6951
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BARIUM COMPOUNDS; FERROELECTRIC MATERIALS; FREQUENCY DEPENDENCE; MONOCRYSTALS; OPTICAL MODES; PERMITTIVITY; PEROVSKITE; TEMPERATURE RANGE 0273-0400 K; ZIRCONATES

Citation Formats

Helal, M. A., Mori, T., and Kojima, S. Softening of infrared-active mode of perovskite BaZrO{sub 3} proved by terahertz time-domain spectroscopy. United States: N. p., 2015. Web. doi:10.1063/1.4919913.
Helal, M. A., Mori, T., & Kojima, S. Softening of infrared-active mode of perovskite BaZrO{sub 3} proved by terahertz time-domain spectroscopy. United States. doi:10.1063/1.4919913.
Helal, M. A., Mori, T., and Kojima, S. Mon . "Softening of infrared-active mode of perovskite BaZrO{sub 3} proved by terahertz time-domain spectroscopy". United States. doi:10.1063/1.4919913.
@article{osti_22399011,
title = {Softening of infrared-active mode of perovskite BaZrO{sub 3} proved by terahertz time-domain spectroscopy},
author = {Helal, M. A. and Mori, T. and Kojima, S.},
abstractNote = {The low-frequency infrared-active optical modes were studied in a barium zirconate, BaZrO{sub 3}, single crystal with the perovskite structure using terahertz (THz) time-domain spectroscopy (TDS). The real and imaginary parts of the dielectric constants were accurately determined in the frequency range between 0.2 and 2.7 THz. Upon cooling from room temperature to 8 K, the lowest-frequency TO1 mode at 2.32 THz showed a pronounced softening to 1.94 THz. The real part of the dielectric constant at 0.5 THz determined by THz-TDS obeys Barrett's relation, and the existence of a plateau confirms that the quantum effects lead to saturation of the soft mode frequencies of the TO1 and TO2 modes below ≈20 K. This is reminiscent of incipient ferroelectrics with the perovskite structure such as CaTiO{sub 3}.},
doi = {10.1063/1.4919913},
journal = {Applied Physics Letters},
issn = {0003-6951},
number = 18,
volume = 106,
place = {United States},
year = {2015},
month = {5}
}