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Dronskowski, R.*; Brckel, T.*; Kohlmann, H.*; Avdeev, M.*; Houben, A.*; Meven, M.*; Hofmann, M.*; Kamiyama, Takashi*; Zobel, M.*; Schweika, W.*; et al.
Zeitschrift fr Kristallographie; Crystalline Materials, 239(5-6), p.139 - 166, 2024/06
Times Cited Count:0 Percentile:0.00(Crystallography)Because of the neutron's special properties, neutron diffraction may be considered one of the most powerful techniques for structure determination of crystalline and related matter. Neutrons can be released from nuclear fission, from spallation processes, and also from low-energy nuclear reactions, and they can then be used in powder, time-of-flight, texture, single crystal, and other techniques, all of which are perfectly suited to clarify crystal and magnetic structures. With high neutron flux and sufficient brilliance, neutron diffraction also excels for diffuse scattering, for in situ and operando studies as well as for high-pressure experiments of today's materials. In this primer, we summarize the current state of neutron diffraction (and how it came to be), but also look at recent advances and new ideas, e.g., the design of new instruments, and what follows from that.
Li, J.*; Li, X.*; Zhang, Y.*; Zhu, J.*; Zhao, E.*; Kofu, Maiko; Nakajima, Kenji; Avdeev, M.*; Liu, P.-F.*; Sui, J.*; et al.
Applied Physics Reviews (Internet), 11(1), p.011406_1 - 011406_8, 2024/03
Times Cited Count:6 Percentile:97.19(Physics, Applied)Park, P.*; Cho, W.*; Kim, C.*; An, Y.*; Avdeev, M.*; Iida, Kazuki*; Kajimoto, Ryoichi; Park, J.-G.*
Physical Review B, 109(6), p.L060403_1 - L060403_7, 2024/02
Times Cited Count:3 Percentile:61.83(Materials Science, Multidisciplinary)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:10 Percentile:79.98(Multidisciplinary Sciences)Cao, Y.*; Zhou, H.*; Khmelevskyi, S.*; Lin, K.*; Avdeev, M.*; Wang, C.-W.*; Wang, B.*; Hu, F.*; Kato, Kenichi*; Hattori, Takanori; et al.
Chemistry of Materials, 35(8), p.3249 - 3255, 2023/04
Times Cited Count:2 Percentile:37.82(Chemistry, Physical)Hydrostatic and chemical pressure are efficient stimuli to alter the crystal structure and are commonly used for tuning electronic and magnetic properties in materials science. However, chemical pressure is difficult to quantify and a clear correspondence between these two types of pressure is still lacking. Here, we study intermetallic candidates for a permanent magnet with a negative thermal expansion (NTE). Based on in situ synchrotron X-ray diffraction, negative chemical pressure is revealed in HoFe on Al doping and quantitatively evaluated by using temperature and pressure dependence of unit cell volume. A combination of magnetization and neutron diffraction measurements also allowed one to compare the effect of chemical pressure on magnetic ordering with that of hydrostatic pressure. Intriguingly, pressure can be used to control suppression and enhancement of NTE. Electronic structure calculations indicate that pressure affected the top of the majority band with respect to the Fermi level, which has implications for the magnetic stability, which in turn plays a critical role in modulating magnetism and NTE. This work presents a good example of understanding the effect of pressure and utilizing it to control properties of functional materials.
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:8 Percentile:63.05(Multidisciplinary Sciences)Li, X.*; Liu, P.-F.*; Zhao, E.*; Zhang, Z.*; Guide, T.*; Le, M. D.*; Avdeev, M.*; Ikeda, Kazutaka*; Otomo, Toshiya*; Kofu, Maiko; et al.
Nature Communications (Internet), 11, p.942_1 - 942_9, 2020/02
Times Cited Count:52 Percentile:91.90(Multidisciplinary Sciences)In high-performance thermoelectric materials, there are two main low thermal conductivity mechanisms: the phonon anharmonic and phonon scattering resulting from the dynamic disorder, which have been successfully revealed by inelastic neutron scattering. Using neutron scattering and ab initio calculations, we report here a mechanism of static local structure distortion combined with phonon-anharmonic-induced ultralow lattice thermal conductivity in -MgAgSb. Since the transverse acoustic phonons are almost fully scattered by the intrinsic distorted rocksalt sublattice in this compound, the heat is mainly transported by the longitudinal acoustic phonons. The ultralow thermal conductivity in -MgAgSb is attributed to its atomic dynamics being altered by the structure distortion, which presents a possible microscopic route to enhance the performance of similar thermoelectric materials.
Hawai, Takafumi*; Nambu, Yusuke*; Ogushi, Kenya*; Du, F.*; Hirata, Yasuyuki*; Avdeev, M.*; Uwatoko, Yoshiya; Sekine, Yurina; Fukazawa, Hiroshi; Ma, J.*; et al.
Physical Review B, 91(18), p.184416_1 - 184416_11, 2015/05
Times Cited Count:17 Percentile:57.11(Materials Science, Multidisciplinary)We investigated the iron-based ladder compounds (Ba, Cs)FeSe, whose parent compounds, BaFeSe and CsFeSe, have different space groups, formal valences of Fe and magnetic structures. Electrical resistivity, specific heat, magnetic susceptibility, X-ray diffraction and powder neutron diffraction measurements were conducted to obtain the temperature and composition phase diagram of this system. Block magnetism seen in BaFeSe is drastically suppressed with Cs doping. In contrast, stripe magnetism observed in CsFeSe more resilient to Ba doping. Novel magnetic structure appears in intermediate compositions, which is similar to the stripe magnetism of CsFeSe but with different inter-ladder spin configuration. Intermediate compounds show insulating behavior, nevertheless finite T-linear contribution in specific heat was obtained at low temperature.
Nambu, Yusuke*; Ogushi, Kenya*; Suzuki, Shumpei*; Du, F.*; Avdeev, M.*; Uwatoko, Yoshiya*; Munakata, Koji*; Fukazawa, Hiroshi; Chi, S.*; Ueda, Yutaka*; et al.
Physical Review B, 85(6), p.064413_1 - 064413_5, 2012/02
Times Cited Count:78 Percentile:92.07(Materials Science, Multidisciplinary)Magnetism in the insulating BaFeSe was examined through susceptibility, specific heat, resistivity and neutron diffraction measurements. After formation of a short-range magnetic correlation, a long-range ordering was observed below 255 K. The transition is obscured by bulk properties. Magnetic moments are arranged to form a Fe ferromagnetic unit, and each Fe stacks antiferromagnetically. This block magnetism is of the third type among magnetic structures of ferrous materials. The magnetic ordering drives unusually large distortion via magnetoelastic coupling.