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Yasui Y, Tansho M, Fujii K, Sakuda Y, Goto A, Ohki S, Mogami Y, Iijima T, Kobayashi S, Kawaguchi S, Osaka K, Ikeda K, Otomo T, Yashima M. Hidden chemical order in disordered Ba 7Nb 4MoO 20 revealed by resonant X-ray diffraction and solid-state NMR. Nat Commun 2023; 14:2337. [PMID: 37095089 PMCID: PMC10126145 DOI: 10.1038/s41467-023-37802-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 03/30/2023] [Indexed: 04/26/2023] Open
Abstract
The chemical order and disorder of solids have a decisive influence on the material properties. There are numerous materials exhibiting chemical order/disorder of atoms with similar X-ray atomic scattering factors and similar neutron scattering lengths. It is difficult to investigate such order/disorder hidden in the data obtained from conventional diffraction methods. Herein, we quantitatively determined the Mo/Nb order in the high ion conductor Ba7Nb4MoO20 by a technique combining resonant X-ray diffraction, solid-state nuclear magnetic resonance (NMR) and first-principle calculations. NMR provided direct evidence that Mo atoms occupy only the M2 site near the intrinsically oxygen-deficient ion-conducting layer. Resonant X-ray diffraction determined the occupancy factors of Mo atoms at the M2 and other sites to be 0.50 and 0.00, respectively. These findings provide a basis for the development of ion conductors. This combined technique would open a new avenue for in-depth investigation of the hidden chemical order/disorder in materials.
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Affiliation(s)
- Yuta Yasui
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1-W4-17, O-okayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Masataka Tansho
- NMR Station, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba, Ibaraki, 305-0003, Japan
| | - Kotaro Fujii
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1-W4-17, O-okayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Yuichi Sakuda
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1-W4-17, O-okayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Atsushi Goto
- NMR Station, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba, Ibaraki, 305-0003, Japan
| | - Shinobu Ohki
- NMR Station, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba, Ibaraki, 305-0003, Japan
| | - Yuuki Mogami
- NMR Station, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba, Ibaraki, 305-0003, Japan
| | - Takahiro Iijima
- Institute of Arts and Sciences, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata, Yamagata, 990-8560, Japan
| | - Shintaro Kobayashi
- Diffraction and Scattering Division, Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan
| | - Shogo Kawaguchi
- Diffraction and Scattering Division, Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan
| | - Keiichi Osaka
- Industrial Application and Partnership Division, Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan
| | - Kazutaka Ikeda
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 203-1 Shirakata, Tokai, Ibaraki, 319-1106, Japan
- J-PARC Center, High Energy Accelerator Research Organization (KEK), 2-4 Shirakata-Shirane, Tokai, Ibaraki, 319-1106, Japan
- School of High Energy Accelerator Science, The Graduate University for Advanced Studies, 203-1 Shirakata, Tokai, Ibaraki, 319-1106, Japan
| | - Toshiya Otomo
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 203-1 Shirakata, Tokai, Ibaraki, 319-1106, Japan
- J-PARC Center, High Energy Accelerator Research Organization (KEK), 2-4 Shirakata-Shirane, Tokai, Ibaraki, 319-1106, Japan
- School of High Energy Accelerator Science, The Graduate University for Advanced Studies, 203-1 Shirakata, Tokai, Ibaraki, 319-1106, Japan
- Graduate School of Science and Engineering, Ibaraki University, 162-1 Shirakata, Tokai, Ibaraki, 319-1106, Japan
| | - Masatomo Yashima
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1-W4-17, O-okayama, Meguro-ku, Tokyo, 152-8551, Japan.
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Cutting Edge of High-Entropy Alloy Superconductors from the Perspective of Materials Research. METALS 2020. [DOI: 10.3390/met10081078] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
High-entropy alloys (HEAs) are a new class of materials which are being energetically studied around the world. HEAs are characterized by a multicomponent alloy in which five or more elements randomly occupy a crystallographic site. The conventional HEA concept has developed into simple crystal structures such as face-centered-cubic (fcc), body-centered-cubic (bcc) and hexagonal-closed packing (hcp) structures. The highly atomic-disordered state produces many superior mechanical or thermal properties. Superconductivity has been one of the topics of focus in the field of HEAs since the discovery of the bcc HEA superconductor in 2014. A characteristic of superconductivity is robustness against atomic disorder or extremely high pressure. The materials research on HEA superconductors has just begun, and there are open possibilities for unexpectedly finding new phenomena. The present review updates the research status of HEA superconductors. We survey bcc and hcp HEA superconductors and discuss the simple material design. The concept of HEA is extended to materials possessing multiple crystallographic sites; thus, we also introduce multisite HEA superconductors with the CsCl-type, α-Mn-type, A15, NaCl-type, σ-phase and layered structures and discuss the materials research on multisite HEA superconductors. Finally, we present the new perspectives of eutectic HEA superconductors and gum metal HEA superconductors.
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Maggard PA, Corbett JD. Formation of gallium dimers in the intermetallic compounds R(5)Ga(3) (R = Sc, Y, Ho, Er, Tm, Lu). Deformation of the Mn(5)Si(3)-type structure. Inorg Chem 2001; 40:1352-7. [PMID: 11300841 DOI: 10.1021/ic0011720] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The R(5)Ga(3) (R = Sc, Y, Ho, Er, Tm, Lu) phases were prepared by high-temperature solid-state techniques. The structure of monoclinic Sc(5)Ga(3) was determined by single-crystal X-ray diffraction means (C2/m, No. 12, Z = 4, a = 8.0793(5) A, b = 14.003(1) A, c = 5.9297(3) A, beta = 90.994(5) degrees ), and those of the isotypic R(5)Ga(3), R = Y, Ho, Er, Tm, Lu, were determined by Guinier powder diffraction. The new Sc(5)Ga(3) structure is a deformation of the hexagonal Mn(5)Si(3) type (P6(3)/mcm) and contains two types of gallium dimers with d(Ga-Ga) = 2.91 and 3.14 A. The closely spaced Sc1 chains in the parent Mn(5)Si(3) type transform to zigzag chains in concert with displacements of the uniformly spaced gallium atoms to form dimers within distorted confacial square antiprisms of Sc. Matrix effects appear important in the different Ga(2) bond lengths. Electronic calculations reveal that the transformation from the hypothetical Mn(5)Si(3) to the Sc(5)Ga(3) type is aided by antibonding Ga-Ga interactions between the dimers that are pushed above E(F) and Ga-Ga and Ga-Sc bonding states just below E(F) that are stabilized. Sc(5)Ga(3) is appropriately metallic. Except for R = Sc, Lu, the arc-melted R(5)Ga(3) compounds above slowly transform on annealing at 1150 degrees C and below into tetragonal Ba(5)Si(3)-type structures.
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Affiliation(s)
- P A Maggard
- Department of Chemistry, Iowa State University, Ames 50014, USA
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