My Research Experiences, Objectives, and Community Services:<\/p>\n
I have worked on the neutron scattering science for more than 25 years using both the reactor- and accelerator-based neutron sources, which include research reactors at JAEA, NIST, ORNL, ANSTO, ILL etc, as well as accelerators such as J-PARC, ISIS and SNS.\u00a0 Main objectives of my research activity are to elucidate novel many-body states in condensed matters such as heavy fermions, frustrated magnets, and quasicrystals.\u00a0 I also served as committee member for several scientific societies or institutions, such as International Union of Crystallography (commission member for magnetic structures and Co-Editor for Journal of Applied Crystallography), and Asia-Oceania Neutron Scattering Association (president).<\/p>\n
My Technical Skills:<\/p>\n
Selected publications:<\/p>\n
Ryuji Tamura, Asuka Ishikawa, Shintaro Suzuki, Takahiro Kotajima, Yujiro Tanaka, Takehito Seki, Naoya Shibata, Tsunetomo Yamada, Takenori Fujii, Chin-Wei Wang, Maxim Avdeev, Kazuhiro Nawa, Daisuke Okuyama, Taku J. Sato<\/span>, Experimental Observation of Long-Range Magnetic Order in Icosahedral Quasicrystals,\u00a0<\/em>Journal of the American Chemical Society\u00a0<\/strong>143(47) 19938-19944 (2021)<\/p>\n After 40 years since the discovery of quasicrystals, we finally found one quasicrystal that shows magnetic long-range order!<\/p>\n<\/div>\n<\/li>\n This work provides the first realistic spin structure model for the complex inter-metallic compound Au72Al14Tb14, also known as “quasicrystal approximate”. \u00a0The intriguing “whirling spin order” was confirmed in this materials, providing new interest in this class of materials for the unconventional magnetism as well as transport properties.<\/li>\n I love this work, since this work was made possible by various talents all over the world. \u00a0The most important was, of course, a devoted effort of the first author Daisuke Okuyama, as he realize SANS under electric current measurement without thermal gradient. \u00a0It was shown experimentally that the magnetic skyrmion lattice a sort of plastic deformation.<\/li>\n Here, we show that the triplon excitation in the coupled dimer compound Ba2CuSi2O6Cl2 has topologically nontrivial character, and indeed can be regarded as a\u00a0bosonic analogue of topological insulator. \u00a0The gap appears at 2.6 meV all over the Brillouin zone, and by a detailed analysis of model spin Hamiltonian it was shown that the surface (much precisely edge) state should form for this compound.<\/p>\n<\/li>\n This work was done by my old friend, Prof. Kittiwit Matan. \u00a0He had a very strange magnon dispersion (linear crossing at a certain k point) spectrum measured in a-Cu2V2O7 for long time, and we discussed the origin for many years. \u00a0 Somehow we came up with an idea of classifying the magnon dispersion relation by symmetry, and found that such a linearly crossing dispersion is due to a certain breaking of inversion symmetry. \u00a0This is the first-of-the-kind type measurement, which we always try.<\/li>\n Taku J. Sato<\/span>, Daisuke Okuyama, Tao Hong, Akiko Kikkawa, Yasujiro Taguchi, Taka-hisa Arima, Yoshinori Tokura, Magnon dispersion shift in the induced ferromagnetic phase of noncentrosymmetric MnSi<\/em>, Phys. Rev. B<\/strong>, 84, 144420-1-7 (2016).<\/p>\n This small piece of work is, I think, one of my best work in recent years. \u00a0I can say that this is done by me, myself. \u00a0I was (and am) trying to elucidate the symmetry effect to the magnon (and other magnetic quasiparticles), and as a very simple example, I tried to measure ferromagnetic magnon in noncentrosymmetric MnSi. \u00a0Experimentally, we needed to realize the inelastic SANS under magnetic field, which was not trivial. \u00a0However, thanks to the teach by Dr. Jeff Lynn some 15 years ago, I knew how I should do, and I did it.<\/li>\n Hiroki Takahashi, Akira Sugimoto, Yusuke Nambu, Touru Yamauchi, Yasuyuki Hirata, Takateru Kawakami, Maxim Avdeev, Kazuyuki Matsubayashi, Fei Du, Chizuru Kawashima,Hideto Soeda, Satoshi Nakano, Yoshiya Uwatoko, Yutaka Ueda, Taku J. Sato<\/span>, Kenya Ohgushi, \u2028Pressure-induced superconductivity in the iron-based ladder material BaFe2<\/sub>S3<\/sub><\/em>, Nature Materials<\/strong> 14 (2015) 1008-1012.<\/p>\n We worked on the Fe-based ladder compounds for a long time, aiming at elucidating how dimensionality changes the superconductivity from 2D Fe-based superconductors. \u00a0But, even metallization was not trivial in the beginning. \u00a0My contribution for this work is small, only neutron diffraction part, and those who did high-pressure work should have the honor.<\/li>\n This was also one of specially remembering works. \u00a0When we did this kagome work, there was a flood of research activities on Fe superconductors. \u00a0We did both, and we published both. \u00a0It was a crazily busy time, but certainly we enjoyed it.<\/li>\n In this work, we show that spin wave excitation spectrum in the parent compound BaFe2As2 of the Fe-based superconductor using a single crystal sample. \u00a0Maybe we need to revisit in future using a better quality single crystal and modern spectrometers, as I still have some interest in the results given in this report, in particular on the itinerant nature.<\/li>\n Hiroaki Kadowaki, Naohiro Doi, Yuji Aoki, Yoshikazu Tabata, Taku J. Sato, Jeffrey W. Lynn, Kazuyuki Matsuhira, Zenji Hiroi,\u2028 Observation of Magnetic Monopoles in Spin Ice<\/em>,\u2028 J. Phys. Soc. Jpn., 78 (2009) 103706-1-4.<\/p>\n This work was done with my two mentors. \u00a0One day in 2008, one of my former advisors called me up and says “let’s observe magnetic monopoles.” \u00a0I thought he was gone crazy, but was not. \u00a0A theoretical expectation of forming magnetic monopoles in pyrochlore compounds were experimentally confirmed in this work using neutron scattering and simulations. \u00a0Although my contribution is not so large (only experimental neutron part), I love this work.<\/li>\n M. de Boissieu, S. Francoual, M. Mihalkovic, K. Shibata, A. Q. R. Baron, Y. Sidis, T. Ishimasa, D. Wu, T. Lograsso, L.-P. Regnault, F. Gahler, S. Tsutsui, B. Hennion, P. Bastie, T. J. Sato<\/span>, H. Takakura, R. Currat and A. P. Tsai,\u2028 Lattice dynamics of the Zn-Mg-Sc icosahedral quasicrystal and its Zn-Sc periodic 1\/1 approximant,<\/em> \u2028Nature Materials<\/strong> 6 (2007) 977-984.<\/p>\n This is the complete work of atomic excitations in quasicrystal and approximant using both the neutron and x-ray inelastic scattering. \u00a0 My contribution is small, only a very small part in neutron scattering, but I am very honored to work with the team of quasicrystal expertise.<\/li>\n This is the first review paper summarizing our quasicrystal magnetism research until early 00′.<\/li>\n When I was at NIST (2001-2003), I tried to learn things that are new to me. \u00a0This is one of them. \u00a0We did neutron scattering on the triangular lattice compound YMnO3, and set the interaction parameters, and well as detected spin fluctuations around TN.<\/li>\n This is also a study made when I was at NIST. \u00a0 A comparative study on the A-site disordered and ordered perovskites clearly shows different inelastic scattering spectrum. \u00a0 Through this work, I learned a new way of using triple-axis spectrometer; a small angle inelastic scattering.<\/li>\n This work is… \u00a0Needless to say, this is a master piece of work that changed the quasicrystal research field. \u00a0The late professor A. P. Tsai, my life-time mentor, did fantastic job in finding quasicrystalline materials, and this is the most impressive one. \u00a0Now, the quasicrystal form in “binary” alloy. \u00a0But much importantly, this “binary” quasicrystal does not have chemical disorder!<\/li>\n This work is the first study of magnetic correlations in the quasicrystal using the single quasicrystalline sample. \u00a0This has two meanings. \u00a0The first is the importance of using the single crystal; single quasicrystal generally excludes impurity inclusion, and hence, did give final conclusion of the absence of magnetic long-range order in this magnetic quasicrystal. \u00a0Second, the 6D magnetic correlation could be concluded by using the Q scans.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":" My Research Experiences, Objectives, and Community Services: I…<\/p>\n","protected":false},"author":40,"featured_media":0,"parent":215,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-671","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www2.tagen.tohoku.ac.jp\/lab\/sato_tj\/wp-json\/wp\/v2\/pages\/671","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www2.tagen.tohoku.ac.jp\/lab\/sato_tj\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www2.tagen.tohoku.ac.jp\/lab\/sato_tj\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www2.tagen.tohoku.ac.jp\/lab\/sato_tj\/wp-json\/wp\/v2\/users\/40"}],"replies":[{"embeddable":true,"href":"https:\/\/www2.tagen.tohoku.ac.jp\/lab\/sato_tj\/wp-json\/wp\/v2\/comments?post=671"}],"version-history":[{"count":13,"href":"https:\/\/www2.tagen.tohoku.ac.jp\/lab\/sato_tj\/wp-json\/wp\/v2\/pages\/671\/revisions"}],"predecessor-version":[{"id":686,"href":"https:\/\/www2.tagen.tohoku.ac.jp\/lab\/sato_tj\/wp-json\/wp\/v2\/pages\/671\/revisions\/686"}],"up":[{"embeddable":true,"href":"https:\/\/www2.tagen.tohoku.ac.jp\/lab\/sato_tj\/wp-json\/wp\/v2\/pages\/215"}],"wp:attachment":[{"href":"https:\/\/www2.tagen.tohoku.ac.jp\/lab\/sato_tj\/wp-json\/wp\/v2\/media?parent=671"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}