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Title: Terahertz dielectric analysis and spin-phonon coupling in multiferroic GeV 4 S 8

Abstract

We present an investigation of the multiferroic lacunar spinel compound GeV 4S 8 using time-domain terahertz spectroscopy. We find three absorptions which either appear or shift at the antiferromagnetic transition temperature, T N=17K, as S=1 magnetic moments develop on vanadium tetrahedra. Two of these absorptions are coupled to the magnetic state and one only appears below the Néel temperature, and is interpreted as a magnon. We also observe isosbestic points in the dielectric constant in both the temperature and frequency domains. Further, we perform an analysis on the isosbestic features to reveal an interesting collapse into a single curve as a function of both frequency and temperature, behavior which exists throughout the phase transitions. This analysis suggests the importance of spectral changes in the terahertz range which are linear in frequency and temperature.

Authors:
 [1];  [2];  [2];  [2];  [1]
  1. The Ohio State Univ., Columbus, OH (United States)
  2. Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1435279
Alternate Identifier(s):
OSTI ID: 1375972
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 96; Journal Issue: 5; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Warren, Matthew T., Pokharel, G., Christianson, A. D., Mandrus, D., and Valdes Aguilar, R. Terahertz dielectric analysis and spin-phonon coupling in multiferroic GeV4S8. United States: N. p., 2017. Web. doi:10.1103/PhysRevB.96.054432.
Warren, Matthew T., Pokharel, G., Christianson, A. D., Mandrus, D., & Valdes Aguilar, R. Terahertz dielectric analysis and spin-phonon coupling in multiferroic GeV4S8. United States. doi:10.1103/PhysRevB.96.054432.
Warren, Matthew T., Pokharel, G., Christianson, A. D., Mandrus, D., and Valdes Aguilar, R. Wed . "Terahertz dielectric analysis and spin-phonon coupling in multiferroic GeV4S8". United States. doi:10.1103/PhysRevB.96.054432.
@article{osti_1435279,
title = {Terahertz dielectric analysis and spin-phonon coupling in multiferroic GeV4S8},
author = {Warren, Matthew T. and Pokharel, G. and Christianson, A. D. and Mandrus, D. and Valdes Aguilar, R.},
abstractNote = {We present an investigation of the multiferroic lacunar spinel compound GeV4S8 using time-domain terahertz spectroscopy. We find three absorptions which either appear or shift at the antiferromagnetic transition temperature, TN=17K, as S=1 magnetic moments develop on vanadium tetrahedra. Two of these absorptions are coupled to the magnetic state and one only appears below the Néel temperature, and is interpreted as a magnon. We also observe isosbestic points in the dielectric constant in both the temperature and frequency domains. Further, we perform an analysis on the isosbestic features to reveal an interesting collapse into a single curve as a function of both frequency and temperature, behavior which exists throughout the phase transitions. This analysis suggests the importance of spectral changes in the terahertz range which are linear in frequency and temperature.},
doi = {10.1103/PhysRevB.96.054432},
journal = {Physical Review B},
number = 5,
volume = 96,
place = {United States},
year = {Wed Aug 23 00:00:00 EDT 2017},
month = {Wed Aug 23 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on August 23, 2018
Publisher's Version of Record

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Cited by: 2 works
Citation information provided by
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