skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Structure and physical properties of EuTa{sub 2}O{sub 6} tungsten bronze polymorph

Abstract

A tetragonal tungsten bronze (TTB) polymorph of EuTa{sub 2}O{sub 6} was prepared and analyzed. EuTa{sub 2}O{sub 6} crystallizes in the centrosymmetric Pnam space group (with unit cell: a = 12.3693, b = 12.4254, and c = 7.7228 Å) isomorphous with orthorhombic β-SrTa{sub 2}O{sub 6}. In contrast to early reports, we see no evidence of deviation from paramagnetic Curie-Weiss behavior among the Eu{sup 2+} 4f{sup 7}spins in EuTa{sub 2}O{sub 6} down to 2 K. Dielectric constant shows a broad peak at ca. 50 K with dielectric dispersion resembling diffuse phase transition. The relaxation time, however, follows a simple (non-freezing) thermally activated process with an activation energy of 92 meV and an attempt frequency of f{sub 0} = 5.79 × 10{sup 12 }Hz. A thermal conductivity of EuTa{sub 2}O{sub 6} shows a low-temperature (T ≈ 30 K) “plateau” region reminiscent of a glass-like behaviour in Nb-based TTB compounds. This behaviour can be attributed to the loosely bound Eu{sup 2+} ions occupying large tricapped trigonal prismatic sites in the EuTa{sub 2}O{sub 6} structure.

Authors:
; ; ;  [1]; ;  [2]
  1. National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan)
  2. Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4M1 (Canada)
Publication Date:
OSTI Identifier:
22318009
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 6; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; DIELECTRIC MATERIALS; EUROPIUM COMPOUNDS; EUROPIUM IONS; NIOBIUM; ORTHORHOMBIC LATTICES; PERMITTIVITY; TANTALATES; THERMAL CONDUCTIVITY; TUNGSTEN BRONZE

Citation Formats

Kolodiazhnyi, T., E-mail: kolodiazhnyi.taras@nims.go.jp, Sakurai, H., Vasylkiv, O., Borodianska, H., Forbes, S., and Mozharivskyj, Y.. Structure and physical properties of EuTa{sub 2}O{sub 6} tungsten bronze polymorph. United States: N. p., 2014. Web. doi:10.1063/1.4893011.
Kolodiazhnyi, T., E-mail: kolodiazhnyi.taras@nims.go.jp, Sakurai, H., Vasylkiv, O., Borodianska, H., Forbes, S., & Mozharivskyj, Y.. Structure and physical properties of EuTa{sub 2}O{sub 6} tungsten bronze polymorph. United States. doi:10.1063/1.4893011.
Kolodiazhnyi, T., E-mail: kolodiazhnyi.taras@nims.go.jp, Sakurai, H., Vasylkiv, O., Borodianska, H., Forbes, S., and Mozharivskyj, Y.. Mon . "Structure and physical properties of EuTa{sub 2}O{sub 6} tungsten bronze polymorph". United States. doi:10.1063/1.4893011.
@article{osti_22318009,
title = {Structure and physical properties of EuTa{sub 2}O{sub 6} tungsten bronze polymorph},
author = {Kolodiazhnyi, T., E-mail: kolodiazhnyi.taras@nims.go.jp and Sakurai, H. and Vasylkiv, O. and Borodianska, H. and Forbes, S. and Mozharivskyj, Y.},
abstractNote = {A tetragonal tungsten bronze (TTB) polymorph of EuTa{sub 2}O{sub 6} was prepared and analyzed. EuTa{sub 2}O{sub 6} crystallizes in the centrosymmetric Pnam space group (with unit cell: a = 12.3693, b = 12.4254, and c = 7.7228 Å) isomorphous with orthorhombic β-SrTa{sub 2}O{sub 6}. In contrast to early reports, we see no evidence of deviation from paramagnetic Curie-Weiss behavior among the Eu{sup 2+} 4f{sup 7}spins in EuTa{sub 2}O{sub 6} down to 2 K. Dielectric constant shows a broad peak at ca. 50 K with dielectric dispersion resembling diffuse phase transition. The relaxation time, however, follows a simple (non-freezing) thermally activated process with an activation energy of 92 meV and an attempt frequency of f{sub 0} = 5.79 × 10{sup 12 }Hz. A thermal conductivity of EuTa{sub 2}O{sub 6} shows a low-temperature (T ≈ 30 K) “plateau” region reminiscent of a glass-like behaviour in Nb-based TTB compounds. This behaviour can be attributed to the loosely bound Eu{sup 2+} ions occupying large tricapped trigonal prismatic sites in the EuTa{sub 2}O{sub 6} structure.},
doi = {10.1063/1.4893011},
journal = {Applied Physics Letters},
number = 6,
volume = 105,
place = {United States},
year = {Mon Aug 11 00:00:00 EDT 2014},
month = {Mon Aug 11 00:00:00 EDT 2014}
}