Superconductivity and its Enhancement under High Pressure in 'F-free' Single Crystals of CeOBiS$_2$
| Autor: | Tanaka, Masashi, Nagao, Masanori, Matsumoto, Ryo, Kataoka, Noriyuki, Ueta, Ikuo, Tanaka, Hiromi, Watauchi, Satoshi, Tanaka, Isao, Takano, Yoshihiko |
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| Rok vydání: | 2017 |
| Předmět: | |
| Zdroj: | J. Alloys and Compd. 722, 467-473 (2017) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1016/j.jallcom.2017.06.125 |
| Popis: | "F-free" CeOBiS$_2$ 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 CeOBiS$_2$ crystallizes with a space group $P4/nmm$ (with lattice parameters of $a$ = 4.0189(6) {\AA}, $c$ = 13.573(2) {\AA}). The bond valence sum estimation and X-ray photoelectron spectroscopy analysis showed that the chemical state of Ce was in the mixed valence of Ce$^{3+}$ and Ce$^{4+}$. The single crystals show superconductivity with zero resistivity at $\sim$1.3 K. This is the first conclusive evidence of superconductivity driven by Ce valence fluctuation in surely non-doped CeOBiS$_2$. The superconducting transition temperature was enhanced up to $\sim$3.8 K by applying hydrostatic pressure. Comment: 27 pages, 8 figures, J. Alloys and Compd. (2017) |
| Databáze: | arXiv |
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