Search

Your search keyword '"Imai, Masaki"' showing total 655 results
Start Over Author "Imai, Masaki"
655 results on '"Imai, Masaki"'

1. Field Dispersion and Strong Coupling of Nuclear-Electron Spin Excitation in MnCO$_3$

Author

Makiuchi, Takahiko, Kikkawa, Takashi, Sichanugrist, Thanaporn, Numata, Junki, Imai, Masaki, Chudo, Hiroyuki, Takahashi, Saburo, and Saitoh, Eiji

Subjects
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Materials Science
Abstract

Hybridized nuclear and electron spin excitation in a MnCO$_3$ crystal, a weakly-anisotropic antiferromagnet, has been investigated. In this material, the hyperfine interaction is strong enough to form a nuclear spin wave. We measure the microwave absorption by a bulk MnCO$_3$ and observe the dispersion representing strong frequency repulsion between electron and nuclear modes due to their hybridization, the signature of nuclear spin wave. Additionally, we observe that the nuclear spin resonance enters a nonlinear regime above a certain excitation power, attributed to the excitation of finite wavenumber nuclear spin waves., Comment: 5 pages, 4 figures

Published
2024

6. Pressure driven magnetic order in Sr$_{1-x}$Ca$_x$Co$_2$P$_2$

Author

Forslund, Ola Kenji, Andreica, Daniel, Sassa, Yasmine, Imai, Masaki, Michioka, Chishiro, Yoshimura, Kazuyoshi, Guguchia, Zurab, Shermadini, Zurab, Khasanov, Rustem, Sugiyama, Jun, and Månsson, Martin

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

The magnetic phase diagram of Sr$_{1-x}$Ca$_x$Co$_2$P$_2$ as a function of hydrostatic pressure and temperature is investigated by means of high pressure muon spin rotation, relaxation and resonance ($\mu^+$SR). The weak pressure dependence for the $x\neq1$ compounds suggests that the rich phase diagram of Sr$_{1-x}$Ca$_x$Co$_2$P$_2$ as a function of $x$ at ambient pressure may not only be attributed to solely chemical pressure effects. The $x=1$ compound on the other hand reveals a high pressure dependence, where the long range magnetic order is fully suppressed at $p_{\rm c2}\approx9.8$~kbar, which seem to be a first order transition. In addition, an intermediate phase consisting of dilute ferromagnetic islands (FMI) is formed above $p_{\rm c1}\approx8$~kbar where they co-exist with a magnetically disordered state. Moreover, such FMI phase seems to consist of an high- (FMI-\textcircled{\small{1}}) and low-temperature (FMI-\textcircled{\small{2}}) region, respectively, separated by a phase boundary at $T_{\rm i}\approx20$~K., Comment: 10 pages, 8 figures

Published
2021

9. Characterization of SARS-CoV-2 Omicron BA.2.75 clinical isolates

Author

Uraki, Ryuta, Iida, Shun, Halfmann, Peter J., Yamayoshi, Seiya, Hirata, Yuichiro, Iwatsuki-Horimoto, Kiyoko, Kiso, Maki, Ito, Mutsumi, Furusawa, Yuri, Ueki, Hiroshi, Sakai-Tagawa, Yuko, Kuroda, Makoto, Maemura, Tadashi, Kim, Taksoo, Mine, Sohtaro, Iwamoto, Noriko, Li, Rong, Liu, Yanan, Larson, Deanna, Fukushi, Shuetsu, Watanabe, Shinji, Maeda, Ken, Wang, Zhongde, Ohmagari, Norio, Theiler, James, Fischer, Will, Korber, Bette, Imai, Masaki, Suzuki, Tadaki, and Kawaoka, Yoshihiro

Published
2023
Full Text
View/download PDF

10. Identification of SARS-CoV-2 Mpro inhibitors containing P1’ 4-fluorobenzothiazole moiety highly active against SARS-CoV-2

Author

Higashi-Kuwata, Nobuyo, Tsuji, Kohei, Hayashi, Hironori, Bulut, Haydar, Kiso, Maki, Imai, Masaki, Ogata-Aoki, Hiromi, Ishii, Takahiro, Kobayakawa, Takuya, Nakano, Kenta, Takamune, Nobutoki, Kishimoto, Naoki, Hattori, Shin-ichiro, Das, Debananda, Uemura, Yukari, Shimizu, Yosuke, Aoki, Manabu, Hasegawa, Kazuya, Suzuki, Satoshi, Nishiyama, Akie, Saruwatari, Junji, Shimizu, Yukiko, Sukenaga, Yoshikazu, Takamatsu, Yuki, Tsuchiya, Kiyoto, Maeda, Kenji, Yoshimura, Kazuhisa, Iida, Shun, Ozono, Seiya, Suzuki, Tadaki, Okamura, Tadashi, Misumi, Shogo, Kawaoka, Yoshihiro, Tamamura, Hirokazu, and Mitsuya, Hiroaki

Published
2023
Full Text
View/download PDF

12. Co-existence of short- and long-range magnetic order in LaCo$_2$P$_2$

Author

Forslund, Ola Kenji, Andreica, Daniel, Ohta, Hiroto, Imai, Masaki, Michioka, Chishiro, Yoshimura, Kazuyoshi, Månsson, Martin, and Sugiyama, Jun

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

The ferromagnetic (FM) nature of the metallic LaCo$_2$P$_2$ was investigated with the positive muon spin rotation, relaxation and resonance ($\mu^+$SR) technique. Transverse and zero field $\mu^+$SR measurements revealed that the compound enters a long range FM ground state at $T_{\rm C}=130.91(65)$~K, consistent with previous studies. Based on the reported FM structure, the internal magnetic field was computed at the muon sites, which were predicted with first principles calculations. The computed result agree well with the experimental data. Moreover, although LaCo$_2$P$_2$ is a paramagnet at higher temperatures $T>160$~K, it enters a short range ordered (SRO) magnetic phase for $T_{\rm C}

Published
2021
Full Text
View/download PDF

15. Enhancement of domain-wall mobility detected by NMR at the angular momentum compensation temperature

Author

Imai, Masaki, Chudo, Hiroyuki, Matsuo, Mamoru, Maekawa, Sadamichi, and Saitoh, Eiji

Subjects
Condensed Matter - Materials Science
Abstract

The angular momentum compensation temperature $T_{\rm A}$ of ferrimagnets has attracted much attention because of high-speed magnetic dynamics near $T_{\rm A}$. We show that NMR can be used to investigate domain wall dynamics near $T_{\rm A}$ in ferrimagnets. We performed $^{57}$Fe-NMR measurements on the ferrimagnet Ho$_3$Fe$_5$O$_{12}$ with $T_{\rm A} = 245$ K. In a multi-domain state, the NMR signal is enhanced by domain wall motion. We found that the NMR signal enhancement shows a maximum at $T_{\rm A}$ in the multi-domain state. The NMR signal enhancement occurs due to increasing domain-wall mobility toward $T_{\rm A}$. We develop the NMR signal enhancement model involves domain-wall mobility. Our study shows that NMR in multi-domain state is a powerful tool to determine $T_{\rm A}$, even from a powder sample and it expands the possibility of searching for angular momentum-compensated materials., Comment: 5 pages, 4 figures

Published
2019
Full Text
View/download PDF

17. Characterization of SARS-CoV-2 Omicron BA.4 and BA.5 isolates in rodents

Author

Uraki, Ryuta, Halfmann, Peter J., Iida, Shun, Yamayoshi, Seiya, Furusawa, Yuri, Kiso, Maki, Ito, Mutsumi, Iwatsuki-Horimoto, Kiyoko, Mine, Sohtaro, Kuroda, Makoto, Maemura, Tadashi, Sakai-Tagawa, Yuko, Ueki, Hiroshi, Li, Rong, Liu, Yanan, Larson, Deanna, Fukushi, Shuetsu, Watanabe, Shinji, Maeda, Ken, Pekosz, Andrew, Kandeil, Ahmed, Webby, Richard J., Wang, Zhongde, Imai, Masaki, Suzuki, Tadaki, and Kawaoka, Yoshihiro

Published
2022
Full Text
View/download PDF

18. Angular momentum compensation manipulation to room temperature of the ferrimagnet Ho$_{3-x}$Dy$_x$Fe$_5$O$_{12}$ detected by the Barnett effect

Author

Imai, Masaki, Chudo, Hiroyuki, Ono, Masao, Harii, Kazuya, Matsuo, Mamoru, Ohnuma, Yuichi, Maekawa, Sadamichi, and Saitoh, Eiji

Subjects
Condensed Matter - Materials Science, Condensed Matter - Other Condensed Matter
Abstract

We demonstrate that the angular momentum compensation temperature $T_A$, at which the net angular momentum in the sample disappears, can be controlled in Ho$_3$Fe$_5$O$_{12}$ by partially substituting Dy for Ho. The $T_A$ can be detected using the Barnett effect, by which mechanical rotation magnetizes an object due to spin-rotation coupling. We found that $T_A$ increases with the Dy content and clarified that the $T_A$ of Ho$_{1.5}$Dy$_{1.5}$Fe$_5$O$_{12}$ coincides with room temperature. The Barnett effect enables us to explore materials applicable to magnetic devices utilizing the angular momentum compensation only by rotating the powder sample at room temperature., Comment: 5pages, 4figure

Published
2019
Full Text
View/download PDF

19. Potent neutralizing broad-spectrum antibody against SARS-CoV-2 generated from dual-antigen-specific B cells from convalescents

Author

Takeshita, Masaru, Fukuyama, Hidehiro, Kamada, Katsuhiko, Matsumoto, Takehisa, Makino-Okamura, Chieko, Lin, Qingshun, Sakuma, Machie, Kawahara, Eiki, Yamazaki, Isato, Uchikubo-Kamo, Tomomi, Tomabechi, Yuri, Hanada, Kazuharu, Hisano, Tamao, Moriyama, Saya, Takahashi, Yoshimasa, Ito, Mutsumi, Imai, Masaki, Maemura, Tadashi, Furusawa, Yuri, Yamayoshi, Seiya, Kawaoka, Yoshihiro, Shirouzu, Mikako, Ishii, Makoto, Saya, Hideyuki, Kondo, Yasushi, Kaneko, Yuko, Suzuki, Katsuya, Fukunaga, Koichi, and Takeuchi, Tsutomu

Published
2023
Full Text
View/download PDF

22. Characterization and antiviral susceptibility of SARS-CoV-2 Omicron BA.2

Author

Uraki, Ryuta, Kiso, Maki, Iida, Shun, Imai, Masaki, Takashita, Emi, Kuroda, Makoto, Halfmann, Peter J., Loeber, Samantha, Maemura, Tadashi, Yamayoshi, Seiya, Fujisaki, Seiichiro, Wang, Zhongde, Ito, Mutsumi, Ujie, Michiko, Iwatsuki-Horimoto, Kiyoko, Furusawa, Yuri, Wright, Ryan, Chong, Zhenlu, Ozono, Seiya, Yasuhara, Atsuhiro, Ueki, Hiroshi, Sakai-Tagawa, Yuko, Li, Rong, Liu, Yanan, Larson, Deanna, Koga, Michiko, Tsutsumi, Takeya, Adachi, Eisuke, Saito, Makoto, Yamamoto, Shinya, Hagihara, Masao, Mitamura, Keiko, Sato, Tetsuro, Hojo, Masayuki, Hattori, Shin-ichiro, Maeda, Kenji, Valdez, Riccardo, Okuda, Moe, Murakami, Jurika, Duong, Calvin, Godbole, Sucheta, Douek, Daniel C., Maeda, Ken, Watanabe, Shinji, Gordon, Aubree, Ohmagari, Norio, Yotsuyanagi, Hiroshi, Diamond, Michael S., Hasegawa, Hideki, Mitsuya, Hiroaki, Suzuki, Tadaki, and Kawaoka, Yoshihiro

Published
2022
Full Text
View/download PDF

23. Observation of gyromagnetic reversal

Author

Imai, Masaki, Ogata, Yudai, Chudo, Hiroyuki, Ono, Masao, Harii, Kazuya, Matsuo, Mamoru, Ohnuma, Yuichi, Maekawa, Sadamichi, and Saitoh, Eiji

Subjects
Condensed Matter - Materials Science
Abstract

We report direct observation of gyromagnetic reversal, which is the sign change of gyromagnetic ratio in a ferrimagnet Ho$_3$Fe$_5$O$_{12}$, by using the Barnett effect measurement technique at low temperatures. The Barnett effect is a phenomenon in which magnetization is induced by mechanical rotation through the coupling between rotation and total angular momentum $J$ of electrons. The magnetization of Ho$_3$Fe$_5$O$_{12}$ induced by mechanical rotation disappears at 135~K and 240~K. The temperatures correspond to the magnetization compensation temperature $T_{\rm M}$ and the angular momentum compensation temperature $T_{\rm A}$, respectively. Between $T_{\rm M}$ and $T_{\rm A}$, the magnetization flips over to be parallel against the angular momentum due to the sign change of gyromagnetic ratio. This study provides an unprecedented technique to explore the gyromagnetic properties., Comment: 4pages,4figures

Published
2018
Full Text
View/download PDF

24. Characterization of a new SARS-CoV-2 variant that emerged in Brazil

Author

Imai, Masaki, Halfmann, Peter J., Yamayoshi, Seiya, Iwatsuki-Horimoto, Kiyoko, Chiba, Shiho, Watanabe, Tokiko, Nakajima, Noriko, Ito, Mutsumi, Kuroda, Makoto, Kiso, Maki, Maemura, Tadashi, Takahashi, Kenta, Loeber, Samantha, Hatta, Masato, Koga, Michiko, Nagai, Hiroyuki, Yamamoto, Shinya, Saito, Makoto, Adachi, Eisuke, Akasaka, Osamu, Nakamura, Morio, Nakachi, Ichiro, Ogura, Takayuki, Baba, Rie, Fujita, Kensuke, Ochi, Junichi, Mitamura, Keiko, Kato, Hideaki, Nakajima, Hideaki, Yagi, Kazuma, Hattori, Shin-ichiro, Maeda, Kenji, Suzuki, Tetsuya, Miyazato, Yusuke, Valdez, Riccardo, Gherasim, Carmen, Furusawa, Yuri, Okuda, Moe, Ujie, Michiko, Lopes, Tiago J. S., Yasuhara, Atsuhiro, Ueki, Hiroshi, Sakai-Tagawa, Yuko, Eisfeld, Amie J., Baczenas, John J., Baker, David A., O’Connor, Shelby L., O’Connor, David H., Fukushi, Shuetsu, Fujimoto, Tsuguto, Kuroda, Yudai, Gordon, Aubree, Maeda, Ken, Ohmagari, Norio, Sugaya, Norio, Yotsuyanagi, Hiroshi, Mitsuya, Hiroaki, Suzuki, Tadaki, and Kawaoka, Yoshihiro

Published
2021

25. SARS-CoV-2 Omicron virus causes attenuated disease in mice and hamsters

Author

Halfmann, Peter J., Iida, Shun, Iwatsuki-Horimoto, Kiyoko, Maemura, Tadashi, Kiso, Maki, Scheaffer, Suzanne M., Darling, Tamarand L., Joshi, Astha, Loeber, Samantha, Singh, Gagandeep, Foster, Stephanie L., Ying, Baoling, Case, James Brett, Chong, Zhenlu, Whitener, Bradley, Moliva, Juan, Floyd, Katharine, Ujie, Michiko, Nakajima, Noriko, Ito, Mutsumi, Wright, Ryan, Uraki, Ryuta, Warang, Prajakta, Gagne, Matthew, Li, Rong, Sakai-Tagawa, Yuko, Liu, Yanan, Larson, Deanna, Osorio, Jorge E., Hernandez-Ortiz, Juan P., Henry, Amy R., Ciuoderis, Karl, Florek, Kelsey R., Patel, Mit, Odle, Abby, Wong, Lok-Yin Roy, Bateman, Allen C., Wang, Zhongde, Edara, Venkata-Viswanadh, Chong, Zhenlu, Franks, John, Jeevan, Trushar, Fabrizio, Thomas, DeBeauchamp, Jennifer, Kercher, Lisa, Seiler, Patrick, Gonzalez-Reiche, Ana Silvia, Sordillo, Emilia Mia, Chang, Lauren A., van Bakel, Harm, Simon, Viviana, Douek, Daniel C., Sullivan, Nancy J., Thackray, Larissa B., Ueki, Hiroshi, Yamayoshi, Seiya, Imai, Masaki, Perlman, Stanley, Webby, Richard J., Seder, Robert A., Suthar, Mehul S., García-Sastre, Adolfo, Schotsaert, Michael, Suzuki, Tadaki, Boon, Adrianus C. M., Diamond, Michael S., and Kawaoka, Yoshihiro

Published
2022
Full Text
View/download PDF

26. Enhanced fusogenicity and pathogenicity of SARS-CoV-2 Delta P681R mutation

Author

Saito, Akatsuki, Irie, Takashi, Suzuki, Rigel, Maemura, Tadashi, Nasser, Hesham, Uriu, Keiya, Kosugi, Yusuke, Shirakawa, Kotaro, Sadamasu, Kenji, Kimura, Izumi, Ito, Jumpei, Wu, Jiaqi, Iwatsuki-Horimoto, Kiyoko, Ito, Mutsumi, Yamayoshi, Seiya, Loeber, Samantha, Tsuda, Masumi, Wang, Lei, Ozono, Seiya, Butlertanaka, Erika P., Tanaka, Yuri L., Shimizu, Ryo, Shimizu, Kenta, Yoshimatsu, Kumiko, Kawabata, Ryoko, Sakaguchi, Takemasa, Tokunaga, Kenzo, Yoshida, Isao, Asakura, Hiroyuki, Nagashima, Mami, Kazuma, Yasuhiro, Nomura, Ryosuke, Horisawa, Yoshihito, Yoshimura, Kazuhisa, Takaori-Kondo, Akifumi, Imai, Masaki, Tanaka, Shinya, Nakagawa, So, Ikeda, Terumasa, Fukuhara, Takasuke, Kawaoka, Yoshihiro, and Sato, Kei

Published
2022
Full Text
View/download PDF

28. Transitions from a Kondo-like diamagnetic insulator into a modulated ferromagnetic metal in $\bm{\mathrm{FeGa}_{3-y}\mathrm{Ge}_y}$

Author

Zhang, Yao, Imai, Masaki, Michioka, Chishiro, Hadano, Yuta, Avila, Marcos A., Takabatake, Toshiro, and Yoshimura, Kazuyoshi

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

One initial and essential question of magnetism is whether the magnetic properties of a material are governed by localized moments or itinerant electrons. Here we expose the case for the weakly ferromagnetic system FeGa$_{3-y}$Ge$_y$ wherein these two opposite models are reconciled, such that the magnetic susceptibility is quantitatively explained by taking into account the effects of spin-spin correlation. With the electron doping introduced by Ge substitution, the diamagnetic insulating parent compound FeGa$_3$ becomes a paramagnetic metal as early as at $ y=0.01 $, and turns into a weakly ferromagnetic metal around the quantum critical point $ y=0.15 $. Within the ferromagnetic regime of FeGa$_{3-y}$Ge$_y$, the magnetic properties are of a weakly itinerant ferromagnetic nature, located in the intermediate regime between the localized and the itinerant dominance. Our analysis implies a potential universality for all itinerant-electron ferromagnets.

Published
2017
Full Text
View/download PDF

29. Soft phonon modes in the vicinity of the structural quantum critical point

Author

Hu, Y. J., Cheung, Y. W., Yu, W. C., Imai, Masaki, Kanagawa, Hibiki, Murakawa, Joichi, Yoshimura, Kazuyoshi, and Goh, Swee K.

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Strongly Correlated Electrons
Abstract

The quasi-skutterudite superconductors $A_3T_4$Sn$_{13}$ ($A$=Sr, Ca; $T$=Ir, Rh, Co) are highly tunable featuring a structural quantum critical point. We construct a temperature-lattice constant phase diagram for these isovalent compounds, establishing Ca$_{3}$Rh$_4$Sn$_{13}$ and Ca$_{3}$Co$_4$Sn$_{13}$ as members close to and far away from the structural quantum critical point, respectively. Deconvolution of the lattice specific heat and the electrical resistivity provide an approximate phonon density of states $F(\omega)$ and the electron-phonon transport coupling function $\alpha_{tr}^2F(\omega)$ for Ca$_{3}$Rh$_4$Sn$_{13}$ and Ca$_{3}$Co$_4$Sn$_{13}$, enabling us to investigate the influence of the structural quantum critical point. Our results support the scenario of phonon softening close to the structural quantum critical point, and explain the enhancement of the coupling strength on approaching structural instability., Comment: 6 pages, 4 figures. Accepted by Phys. Rev. B

Published
2017
Full Text
View/download PDF

31. Potent SARS-CoV-2 neutralizing antibodies with therapeutic effects in two animal models

Author

Takeshita, Masaru, Fukuyama, Hidehiro, Kamada, Katsuhiko, Matsumoto, Takehisa, Makino-Okamura, Chieko, Uchikubo-Kamo, Tomomi, Tomabechi, Yuri, Hanada, Kazuharu, Moriyama, Saya, Takahashi, Yoshimasa, Ishigaki, Hirohito, Nakayama, Misako, Nguyen, Cong Thanh, Kitagawa, Yoshinori, Itoh, Yasushi, Imai, Masaki, Maemura, Tadashi, Furusawa, Yuri, Ueki, Hiroshi, Iwatsuki-Horimoto, Kiyoko, Ito, Mutsumi, Yamayoshi, Seiya, Kawaoka, Yoshihiro, Shirouzu, Mikako, Ishii, Makoto, Saya, Hideyuki, Kondo, Yasushi, Kaneko, Yuko, Suzuki, Katsuya, Fukunaga, Koichi, and Takeuchi, Tsutomu

Published
2022
Full Text
View/download PDF

35. Neutrophil adhesion to vessel walls impairs pulmonary circulation in COVID-19 pathology

Author

Kawaoka, Yoshihiro, primary, Ueki, Hiroshi, additional, Wang, I-Hsuan, additional, Kiso, Maki, additional, Horie, Kenta, additional, Iida, Shun, additional, Mine, Sohtaro, additional, Ujie, Michiko, additional, Hsu, Hung-Wei, additional, Henry, Chen-Hui, additional, Imai, Masaki, additional, Suzuki, Tadaki, additional, Kamitani, Wataru, additional, and Kawakami, Eiryo, additional

Published
2024
Full Text
View/download PDF

37. Syrian hamsters as a small animal model for SARS-CoV-2 infection and countermeasure development

Author

Imai, Masaki, Iwatsuki-Horimoto, Kiyoko, Hatta, Masato, Loeber, Samantha, Halfmann, Peter J., Nakajima, Noriko, Watanabe, Tokiko, Ujie, Michiko, Takahashi, Kenta, Ito, Mutsumi, Yamada, Shinya, Fan, Shufang, Chiba, Shiho, Kuroda, Makoto, Guan, Lizheng, Takada, Kosuke, Armbrust, Tammy, Balogh, Aaron, Furusawa, Yuri, Okuda, Moe, Ueki, Hiroshi, Yasuhara, Atsuhiro, Sakai-Tagawa, Yuko, Lopes, Tiago J. S., Kiso, Maki, Yamayoshi, Seiya, Kinoshita, Noriko, Ohmagari, Norio, Hattori, Shin-ichiro, Takeda, Makoto, Mitsuya, Hiroaki, Krammer, Florian, Suzuki, Tadaki, and Kawaoka, Yoshihiro

Published
2020

39. Second-order Structural Transition in Superconductor La$_3$Co$_4$Sn$_{13}$

Author

Cheung, Y. W., Zhang, J. Z., Zhu, J. Y., Yu, W. C., Hu, Y. J., Wang, D. G., Otomo, Yuka, Iwasa, Kazuaki, Kaneko, Koji, Imai, Masaki, Kanagawa, Hibiki, Yoshimura, Kazuyoshi, and Goh, Swee K.

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Strongly Correlated Electrons
Abstract

The quasi-skutterudite superconductor La$_3$Co$_4$Sn$_{13}$ undergoes a phase transition at $T^*=152$ K. By measuring the temperature dependence of heat capacity, electrical resistivity, and the superlattice reflection intensity using X-ray, we explore the character of the phase transition at $T^*$. Our lattice dynamic calculations found imaginary phonon frequencies around the ${\bf M}$ point, when the high temperature structure is used in the calculations, indicating that the structure is unstable at the zero temperature limit. The combined experimental and computational results establish that $T^*$ is associated with a second-order structural transition with $\bf{q}$=(0.5, 0.5, 0) (or the ${\bf M}$ point). Further electronic bandstructure calculations reveal Fermi surface sheets with low curvature segments, which allow us to draw qualitative comparison with both Sr$_3$Ir$_4$Sn$_{13}$ and Sr$_3$Rh$_4$Sn$_{13}$ in which similar physics has been discussed recently., Comment: 6 pages, 4 figures, accepted for publication in Phys. Rev. B (Rapid Com)

Published
2016
Full Text
View/download PDF

41. Strong Coupling Superconductivity in the Vicinity of the Structural Quantum Critical Point in (Ca$_x$Sr$_{1-x}$)$_3$Rh$_4$Sn$_{13}$

Author

Yu, Wing Chi, Cheung, Yiu Wing, Saines, Paul J., Imai, Masaki, Matsumoto, Takuya, Michioka, Chishiro, Yoshimura, Kazuyoshi, and Goh, Swee K.

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Strongly Correlated Electrons
Abstract

The family of the superconducting quasi-skutterudites (Ca$_x$Sr$_{1-x}$)$_3$Rh$_4$Sn$_{13}$ features a structural quantum critical point at $x_c=0.9$, around which a dome-shaped variation of the superconducting transition temperature $T_c$ is found. Using specific heat, we probe the normal and the superconducting states of the entire series straddling the quantum critical point. Our analysis indicates a significant lowering of the effective Debye temperature on approaching $x_c$, which we interpret as a result of phonon softening accompanying the structural instability. Furthermore, a remarkably large enhancement of $2\Delta/k_BT_c$ and $\Delta C/\gamma T_c$ beyond the Bardeen-Cooper-Schrieffer (BCS) values is found in the vicinity of the structural quantum critical point. The phase diagram of (Ca$_{x}$Sr$_{1-x}$)$_3$Rh$_4$Sn$_{13}$ thus provides a model system to study the interplay between structural quantum criticality and strong electron-phonon coupling superconductivity., Comment: 6 pages, accepted for publication in Phys. Rev. Lett

Published
2015
Full Text
View/download PDF

43. Anomalous Itinerant-Electron Metamagnetic Transition in the Layered Sr1-xCaxCo2P2 System

Author

Imai, Masaki, Michioka, Chishiro, Ohta, Hiroto, Matsuo, Akira, Kindo, Koichi, Ueda, Hiroaki, and Yoshimura, Kazuyoshi

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

We report magnetic properties of the layered itinerant system, Sr$_{1-x}$Ca$_x$Co$_2$P$_2$ in the magnetic field up to 70 T. As for the exchange-enhanced Pauli paramagnetic metal SrCo$_2$P$_2$, the magnetization curve shows two characteristic anomalies. The low-field anomaly is small without obvious hysteresis, and the high-field one is a typical behavior of the itinerant-electron metamagnetic transition (IEMT). Such a successive transition in the magnetization curve cannot be explained by the conventional phenomenological theory for IEMT due to the Landau expansion of the free energy, but by the extended Landau expansion theory with distinguishable two energy states. In the systematical study of Sr$_{1-x}$Ca$_x$Co$_2$P$_2$, furthermore, the metamagnetic transition field decreases and goes to zero as $x$ increases up to 0.5, indicating that the ferromagnetic quantum critical point (QCP) exists at $x \sim 0.5$., Comment: 10 pages, 4 figure, one column

Published
2014
Full Text
View/download PDF

44. ACE2-like carboxypeptidase B38-CAP protects from SARS-CoV-2-induced lung injury

Author

Yamaguchi, Tomokazu, Hoshizaki, Midori, Minato, Takafumi, Nirasawa, Satoru, Asaka, Masamitsu N., Niiyama, Mayumi, Imai, Masaki, Uda, Akihiko, Chan, Jasper Fuk-Woo, Takahashi, Saori, An, Jianbo, Saku, Akari, Nukiwa, Ryota, Utsumi, Daichi, Kiso, Maki, Yasuhara, Atsuhiro, Poon, Vincent Kwok-Man, Chan, Chris Chung-Sing, Fujino, Yuji, Motoyama, Satoru, Nagata, Satoshi, Penninger, Josef M., Kamada, Haruhiko, Yuen, Kwok-Yung, Kamitani, Wataru, Maeda, Ken, Kawaoka, Yoshihiro, Yasutomi, Yasuhiro, Imai, Yumiko, and Kuba, Keiji

Published
2021
Full Text
View/download PDF

45. Influenza A variants with reduced susceptibility to baloxavir isolated from Japanese patients are fit and transmit through respiratory droplets

Author

Imai, Masaki, Yamashita, Makoto, Sakai-Tagawa, Yuko, Iwatsuki-Horimoto, Kiyoko, Kiso, Maki, Murakami, Jurika, Yasuhara, Atsuhiro, Takada, Kosuke, Ito, Mutsumi, Nakajima, Noriko, Takahashi, Kenta, Lopes, Tiago J. S., Dutta, Jayeeta, Khan, Zenab, Kriti, Divya, van Bakel, Harm, Tokita, Akifumi, Hagiwara, Haruhisa, Izumida, Naomi, Kuroki, Haruo, Nishino, Tamon, Wada, Noriyuki, Koga, Michiko, Adachi, Eisuke, Jubishi, Daisuke, Hasegawa, Hideki, and Kawaoka, Yoshihiro

Published
2020
Full Text
View/download PDF

46. Magnetic properties in layered (K, Rb and Cs)Co2Se2 with ThCr2Si2_type structure

Author

Yang, Jinhu, Chen, Bin, Wang, Hangdong, Mao, Qianhui, Imai, Masaki, Yoshimura, Kazuyoshi, and Fang, Minghu

Subjects
Condensed Matter - Superconductivity
Abstract

The magnetic properties of ThCr_2Si_2-type single crystals ACo_2Se_2 (A = K, Rb and Cs) have been investigated by magnetic susceptibility and isothermal magnetization measurements at various temperatures. The ferromagnetic phase transition temperatures are estimated as $\approx$ 74 K and 76 K and 62 K for A = K, Rb and Cs (in case of high magnetic field), respectively. The susceptibility data in the paramagnetic state obey the modified Curie-Weiss law quite well and the derived effective magnetic moments of the Co atom are about 2.21, 2.04 and 2.04 \mu_B/Co and the corresponding spontaneous moments derived at the ground state are 0.72, 0.59 and 0.52 \mu_B/Co as well as the generalized Rhodes-Wohlfarth ratios as 3.07, 3.42 and 3.96 for A= K, Rb and Cs, respectively. The magnetic moment aligns within ab-plane and a metamagnetism-like behavior occurs at a field of 3.5 T in CsCo_2Se_2 with H//ab-plane. The magnetic properties in this system were discussed within the frameworks of the self-consistent renormalization (SCR) and Takahashi's theory of spin fluctuations., Comment: 8 pages, 9 figures

Published
2013
Full Text
View/download PDF

49. Characterization of an EG.5.1 clinical isolate in vitro and in vivo

Author

Uraki, Ryuta, primary, Kiso, Maki, additional, Iwatsuki-Horimoto, Kiyoko, additional, Yamayoshi, Seiya, additional, Ito, Mutsumi, additional, Chiba, Shiho, additional, Sakai-Tagawa, Yuko, additional, Imai, Masaki, additional, Kashima, Yukie, additional, Koga, Michiko, additional, Fuwa, Noriko, additional, Okumura, Nobumasa, additional, Hojo, Masayuki, additional, Iwamoto, Noriko, additional, Kato, Hideaki, additional, Nakajima, Hideaki, additional, Ohmagari, Norio, additional, Yotsuyanagi, Hiroshi, additional, Suzuki, Yutaka, additional, and Kawaoka, Yoshihiro, additional

Published
2023
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results