Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Tsuru, Tomohito; Han, S.*; Matsuura, Shutaro*; Chen, Z.*; Kishida, Kyosuke; Lobzenko, I.; Rao, S.*; Woodward, C.*; George, E.*; Inui, Haruyuki*
Nature Communications (Internet), 15, p.1706_1 - 1706_10, 2024/02
Times Cited Count:0Refractory high-entropy alloys (RHEAs) have attracted attention because of their potential for use in ultrahigh-temperature applications. Unfortunately, their body-centered-cubic (BCC) crystal structures make them more brittle than the ductile and fracture-resistant face-centered-cubic (FCC) HEAs. RHEAs also display significantly lower creep strengths than a leading Ni-base superalloy and its FCC matrix. To overcome these drawbacks and develop RHEAs into viable structural materials, improved fundamental understanding is needed of factors that control strength and ductility. Here we investigate two model RHEAs, TiZrHfNbTa and VNbMoTaW, and show that the former is plastically compressible down to 77 K, whereas the latter is not below 298 K. We find that hexagonal close-packed (HCP) elements in TiZrHfNbTa lower its dislocation core energy, increase its lattice distortion, and lower its shear modulus relative to VNbMoTaW whose elements are all BCC, leading to the formers higher ductility and modulus-normalized yield strength. Consistent with our yield strength models, primarily screw dislocations are present in TiZrHfNbTa after deformation, but equal numbers of edge and screw segments in VNbTaMoW. Dislocation cores are compact in VNbTaMoW and extended in TiZrHfNbTa, and different macroscopic slip planes are activated in the two RHEAs, which we attribute to the concentration of HCP elements. Our findings demonstrate how electronic structure changes related to the ratio of HCP to BCC elements can be used to control strength, ductility, and slip behavior to develop the next generation of high-temperature materials for more efficient power plants and transportation.
Amekura, Hiroshi*; Chettah, A.*; Narumi, Kazumasa*; Chiba, Atsuya*; Hirano, Yoshimi*; Yamada, Keisuke*; Yamamoto, Shunya*; Leino, A. A.*; Djurabekova, F.*; Nordlund, K.*; et al.
Nature Communications (Internet), 15, p.1786_1 - 1786_10, 2024/02
Injecting high-energy heavy ions in the electronic stopping regime into solids can create cylindrical damage zones called latent ion tracks. Although these tracks form in many materials, none have ever been observed in diamond, even when irradiated with high-energy GeV uranium ions. Here we report the first observation of ion track formation in diamond irradiated with 2-9 MeV C fullerene ions. Depending on the ion energy, the mean track length (diameter) changed from 17 (3.2) nm to 52 (7.1) nm. High resolution scanning transmission electron microscopy (HR-STEM) indicated the amorphization in the tracks, in which -bonding signal from graphite was detected by the electron energy loss spectroscopy (EELS).
Park, P.*; Cho, W.*; Kim, C.*; An, Y.*; Kang, Y.-G.*; Avdeev, M.*; Sibille, R.*; Iida, Kazuki*; Kajimoto, Ryoichi; Lee, K. H.*; et al.
Nature Communications (Internet), 14, p.8346_1 - 8346_9, 2023/12
Times Cited Count:0 Percentile:0(Multidisciplinary Sciences)Bao, S.*; Gu, Z.-L.*; Shangguan, Y.*; Huang, Z.*; Liao, J.*; Zhao, X.*; Zhang, B.*; Dong, Z.-Y.*; Wang, W.*; Kajimoto, Ryoichi; et al.
Nature Communications (Internet), 14, p.6093_1 - 6093_9, 2023/09
Times Cited Count:1 Percentile:61.99(Multidisciplinary Sciences)Ishihara, Kota*; Roppongi, Masaki*; Kobayashi, Masayuki*; Imamura, Kumpei*; Mizukami, Yuta*; Sakai, Hironori; Opletal, P.; Tokiwa, Yoshifumi; Haga, Yoshinori; Hashimoto, Kenichiro*; et al.
Nature Communications (Internet), 14, p.2966_1 - 2966_7, 2023/05
Times Cited Count:5 Percentile:92.42(Multidisciplinary Sciences)The superconducting symmetry of the heavy fermion uranium-based superconductor UTe is investigated using low temperature penetration depth measurements. The anisotropic low-energy quasiparticle excitations indicates multiple superconducting components in a chiral complex form. The most consistent is a chiral non-unitary state.
Chong, Y.*; Gholizadeh, R.*; Tsuru, Tomohito; Zhang, R.*; Inoue, Koji*; Gao, W.*; Godfrey, A.*; Mitsuhara, Masatoshi*; Morris, J. W. Jr.*; Minor, A. M.*; et al.
Nature Communications (Internet), 14, p.404_1 - 404_11, 2023/02
Times Cited Count:6 Percentile:93.59(Multidisciplinary Sciences)Interstitial oxygen embrittles titanium, particularly at cryogenic temperatures, which necessitates a stringent control of oxygen content in fabricating titanium and its alloys. Here, we propose a structural strategy, via grain refinement, to alleviate this problem. Compared to a coarse-grained counterpart that is extremely brittle at 77K, the uniform elongation of an ultrafine-grained (UFG) microstructure (grain size 2.0 m) in Ti-0.3wt.%O was successfully increased by an order of magnitude, maintaining an ultrahigh yield strength inherent to the UFG microstructure. This unique strength-ductility synergy in UFG Ti-0.3wt.%O was achieved via the combined effects of diluted grain boundary segregation of oxygen that helps to improve the grain boundary cohesive energy and enhanced dislocation activities that contribute to the excellent strain hardening ability. The present strategy could not only boost the potential applications of high strength Ti-O alloys at low temperatures, but could also be applied to other alloy systems, where interstitial solution hardening results into an undesirable loss of ductility.
Schoelmerich, M. C.*; Oubouter, H. T.*; Sachdeva, R.*; Penev, P. I.*; Amano, Yuki; West-Roberts, J.*; Welte, C. U.*; Banfield, J. F.*
Nature Communications (Internet), 13, p.7085_1 - 7085_11, 2022/11
Times Cited Count:6 Percentile:73.27(Multidisciplinary Sciences)Xu, S.*; Odaira, Takumi*; Sato, Shunsuke*; Xu, X.*; Omori, Toshihiro*; Harjo, S.; Kawasaki, Takuro; Seiner, H.*; Zoubkov, K.*; Murakami, Yasukazu*; et al.
Nature Communications (Internet), 13, p.5307_1 - 5307_8, 2022/09
Times Cited Count:8 Percentile:66.14(Multidisciplinary Sciences)Funatsu, Takuya*; Kanai, Shun*; Ieda, Junichi; Fukami, Shunsuke*; Ohno, Hideo*
Nature Communications (Internet), 13, p.4079_1 - 4079_8, 2022/07
Times Cited Count:2 Percentile:34.67(Multidisciplinary Sciences)Modulation of the energy landscape by external perturbations governs various thermally-activated phenomena, described by the Arrhenius law. Thermal fluctuation of nanoscale magnetic tunnel junctions with spin-transfer torque (STT) shows promise for unconventional computing, whereas its rigorous representation, based on the Neel-Arrhenius law, has been controversial. In particular, the exponents for thermally-activated switching rate therein, have been inaccessible with conventional thermally-stable nanomagnets with decade-long retention time. Here we approach the Neel-Arrhenius law with STT utilising superparamagnetic tunnel junctions that have high sensitivity to external perturbations and determine the exponents through several independent measurements including homodyne-detected ferromagnetic resonance, nanosecond STT switching, and random telegraph noise. Furthermore, we show that the results are comprehensively described by a concept of local bifurcation observed in various physical systems. The findings demonstrate the capability of superparamagnetic tunnel junction as a useful tester for statistical physics as well as sophisticated engineering of probabilistic computing hardware with a rigorous mathematical foundation.
Chen, L.*; Mao, C.*; Chung, J.-H.*; Stone, M. B.*; Kolesnikov, A. I.*; Wang, X.*; Murai, Naoki; Gao, B.*; Delaire, O.*; Dai, P.*
Nature Communications (Internet), 13, p.4037_1 - 4037_7, 2022/07
Times Cited Count:8 Percentile:53.42(Multidisciplinary Sciences)Maeyama, Shinya*; Watanabe, Tomohiko*; Nakata, Motoki*; Nunami, Masanori*; Asahi, Yuichi; Ishizawa, Akihiro*
Nature Communications (Internet), 13, p.3166_1 - 3166_8, 2022/06
Times Cited Count:11 Percentile:93.39(Multidisciplinary Sciences)Turbulent transport is a key physics process for confining magnetic fusion plasma. Recent theoretical and experimental studies of existing fusion experimental devices revealed the existence of cross-scale interactions between small (electron)-scale and large (ion)-scale turbulence. Since conventional turbulent transport modelling lacks cross-scale interactions, it should be clarified whether cross-scale interactions are needed to be considered in future experiments on burning plasma, whose high electron temperature is sustained with fusion-born alpha particle heating. Here, we present supercomputer simulations showing that electron scale turbulence in high electron temperature plasma can affect the turbulent transport of not only electrons but also fuels and ash. Electron-scale turbulence disturbs the trajectories of resonant electrons responsible for ion-scale micro-instability and suppresses large-scale turbulent fluctuations. Simultaneously, ion-scale turbulent eddies also suppress electron-scale turbulence. These results indicate a mutually exclusive nature of turbulence with disparate scales. We demonstrate the possibility of reduced heat flux via cross-scale interactions.
Yu, Y.*; Yang, C.*; Baggioli, M.*; Phillips, A. E.*; Zaccone, A.*; Zhang, L.*; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Yu, D.*; Hong, L.*
Nature Communications (Internet), 13, p.3649_1 - 3649_10, 2022/06
Times Cited Count:8 Percentile:81.66(Multidisciplinary Sciences)Otsuka, Takaharu; Abe, Takashi*; Yoshida, Toru*; Tsunoda, Yusuke*; Shimizu, Noritaka*; Itagaki, Naoyuki*; Utsuno, Yutaka; Vary, J. P.*; Maris, P.*; Ueno, Hideki*
Nature Communications (Internet), 13, p.2234_1 - 2234_10, 2022/04
Times Cited Count:17 Percentile:95.19(Multidisciplinary Sciences)no abstracts in English
Luo, P.*; Zhai, Y.*; Falus, P.*; Garca Sakai, V.*; Hartl, M.*; Kofu, Maiko; Nakajima, Kenji; Faraone, A.*; Z, Y.*
Nature Communications (Internet), 13, p.2092_1 - 2092_9, 2022/04
Times Cited Count:3 Percentile:58.88(Multidisciplinary Sciences)Takagi, Rina*; Matsuyama, Naofumi*; Ukleev, V.*; Yu, L.*; White, J. S.*; Francoual, S.*; Mardegan, J. R. L.*; Hayami, Satoru*; Saito, Hiraku*; Kaneko, Koji; et al.
Nature Communications (Internet), 13, p.1472_1 - 1472_7, 2022/03
Times Cited Count:55 Percentile:99.61(Multidisciplinary Sciences)Zhang, J.*; Chen, M.*; Chen, J.*; Yamamoto, Kei; Wang, H.*; Hamdi, M.*; Sun, Y.*; Wagner, K.*; He, W.*; Zhang, Y.*; et al.
Nature Communications (Internet), 12, p.7258_1 - 7258_8, 2021/12
Times Cited Count:14 Percentile:77.64(Multidisciplinary Sciences)Ono, Koki*; Higomoto, Toshiya*; Saito, Yugo*; Uchino, Shun; Nishida, Yusuke*; Takahashi, Yoshiro*
Nature Communications (Internet), 12, p.6724_1 - 6724_8, 2021/11
Times Cited Count:8 Percentile:69.3(Multidisciplinary Sciences)Quantum transport is ubiquitous in physics. So far, quantum transport between terminals has been extensively studied in solid state systems from the fundamental point of views such as the quantized conductance to the applications to quantum devices. Recent works have demonstrated a cold-atom analog of a mesoscopic conductor by engineering a narrow conducting channel with optical potentials, which opens the door for a wealth of research of atomtronics emulating mesoscopic electronic devices and beyond. Here we realize an alternative scheme of the quantum transport experiment with ytterbium atoms in a two-orbital optical lattice system. Our system consists of a multi-component Fermi gas and a localized impurity, where the current can be created in the spin space by introducing the spin-dependent interaction with the impurity. We demonstrate a rich variety of localized-impurity-induced quantum transports, which paves the way for atomtronics exploiting spin degrees of freedom.
Fittipaldi, R.*; Hartmann, R.*; Mercaldo, M. T.*; Komori, Sachio*; Bjrlig, A.*; Higemoto, Wataru; Maeno, Yoshiteru*; Di Bernardo, A.*; 18 of others*
Nature Communications (Internet), 12, p.5792_1 - 5792_9, 2021/10
Times Cited Count:12 Percentile:64.44(Multidisciplinary Sciences)The layered oxide perovskite SrRuO, which has been intensively investigated due to its unusual properties. Whilst the debate on the symmetry of the superconducting state in SrRuO is still ongoing, a deeper understanding of the SrRuO normal state appears crucial as this is the background in which electron pairing occurs. Here, by using low-energy muon spin spectroscopy we discover the existence of surface magnetism in SrRuO at an onset temperature higher than 50 K. Our observations set a reference for the discovery of the same magnetic phase in other materials.
Chen, Y.*; Sato, Masahiro*; Tang, Y.*; Shiomi, Yuki*; Oyanagi, Koichi*; Masuda, Takatsugu*; Nambu, Yusuke*; Fujita, Masaki*; Saito, Eiji
Nature Communications (Internet), 12, p.5199_1 - 5199_7, 2021/08
Times Cited Count:8 Percentile:61.37(Multidisciplinary Sciences)Okuma, Ryutaro*; Kofu, Maiko; Asai, Shinichiro*; Avdeev, M.*; Koda, Akihiro*; Okabe, Hirotaka*; Hiraishi, Masatoshi*; Takeshita, Soshi*; Kojima, Kenji*; Kadono, Ryosuke*; et al.
Nature Communications (Internet), 12, p.4382_1 - 4382_7, 2021/07
Times Cited Count:6 Percentile:61.42(Multidisciplinary Sciences)