Kyushu Institute of Technology Academic Repository
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Single crystal X-ray structural analysis, Ce valence evaluation, Resistivity under high pressure, BiS2-based superconductors, Layered mixed-anion compounds
Graduate School of Engineering, Kyushu Institute of Technology, 1-1 Sensui-cho, Tobata, Kitakyushu, 804-8550, Japan, WPI-MANA, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
University of Yamanashi, 7-32 Miyamae, Kofu, Yamanashi 400-8511, Japan
WPI-MANA, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
National Institute of Technology, Yonago College, 4448 Hikona, Yonago, Tottori 683-8502, Japan
University of Yamanashi, 7-32 Miyamae, Kofu, Yamanashi 400-8511, Japan
National Institute of Technology, Yonago College, 4448 Hikona, Yonago, Tottori 683-8502, Japan
University of Yamanashi, 7-32 Miyamae, Kofu, Yamanashi 400-8511, Japan
University of Yamanashi, 7-32 Miyamae, Kofu, Yamanashi 400-8511, Japan
WPI-MANA, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
抄録
“F-free” CeOBiS2 single crystals have successfully grown, thoroughly eliminating a concern about F-contamination by using a high-purity CsCl flux. The obtained crystals have a plate-like shape with a size of 1.0–3.0 mm in the well-developed plane. Single crystal X-ray structural analysis clearly revealed that the CeOBiS2 crystallizes with a space group P4/nmm (with lattice parameters of a = 4.0189 (6) Å, c = 13.573 (2) Å). The bond valence sum estimation and X-ray photoelectron spectroscopy analysis showed that the chemical state of Ce was in the mixed valence of Ce3+ and Ce4+. The single crystals show superconductivity with zero resistivity at ∼1.3 K. This is the first conclusive evidence of superconductivity driven by Ce valence fluctuation in surely non-doped CeOBiS2. The superconducting transition temperature was enhanced up to ∼3.8 K by applying hydrostatic pressure.
雑誌名
Journal of Alloys and Compounds
巻
722
号
25
ページ
467 - 473
発行年
2017-06-12
出版者
Elsevier
ISSN
0925-8388
書誌レコードID
AA10817249
DOI
https://doi.org/10.1016/j.jallcom.2017.06.125
権利
Copyright (c) 2017 Elsevier B.V. All rights reserved.
Superconductivity and its enhancement under high pressure in “F-free” single crystals of CeOBiS2
scunit-2017_02.pdf
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