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Iyo A, Hase I, Kawashima K, Ishida S, Kito H, Takeshita N, Oka K, Fujihisa H, Gotoh Y, Yoshida Y, Eisaki H. Synthesis and Superconductivity of a Strontium Digermanide SrGe 2-δ with ThSi 2 Structure. Inorg Chem 2017; 56:8590-8595. [PMID: 28657309 DOI: 10.1021/acs.inorgchem.7b01446] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have succeeded in crystallizing a new strontium digermanide (SrGe2-δ) with the ThSi2-type structure (tetragonal SrGe2), which is theoretically predicted to compete with the EuGe2-type one (trigonal SrGe2) under pressure. The tetragonal SrGe2 appeared as a metastable phase in samples at approximately 900 °C under a pressure of 2 GPa. X-ray diffraction studies show that the tetragonal SrGe2 is formed by the reaction between trigonal SrGe2 and excess Sr. The composition of the tetragonal SrGe2 was analyzed to be SrGe1.66(4). Lattice parameters for the tetragonal SrGe2 are determined to be a = 4.559(4) Å and c = 14.42(1) Å. The tetragonal SrGe2 shows metallic resistivity behavior and exhibits superconductivity with a critical temperature (Tc) of 7.3 K, which is the highest among compounds with the ThSi2-type structure. Superconducting properties of the tetragonal SrGe2, such as the upper critical field, and the effect of pressure on Tc, are presented and superconductivity is discussed on the basis of electronic band structure calculations.
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Affiliation(s)
- Akira Iyo
- National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Izumi Hase
- National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Kenji Kawashima
- National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan.,IMRA Material R&D Co. Ltd. , 2-1 Asahi-machi, Kariya, Aichi 448-0032, Japan
| | - Shigeyuki Ishida
- National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Hijiri Kito
- National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Nao Takeshita
- National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Kunihiko Oka
- National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Hiroshi Fujihisa
- National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Yoshito Gotoh
- National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Yoshiyuki Yoshida
- National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Hiroshi Eisaki
- National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
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Tsang T, Gschneidner KA, Schmidt FA, Thome DK. Low-temperature heat capacity of electrotransport-purified scandium, yttrium, gadolinium, and lutetium. PHYSICAL REVIEW. B, CONDENSED MATTER 1985; 31:235-244. [PMID: 9935416 DOI: 10.1103/physrevb.31.235] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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