Takatsugu Masuda

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Name
Takatsugu Masuda
Affiliation
The University of Tokyo
Section
Neutron Science Laboratory Affiliated to the ISSP

Research Areas

 
 

Academic & Professional Experience

 
Apr 2010
 - 
Today
Associate professor, Institute for Solid State Physics, University of Tokyo
 
Apr 2005
 - 
Mar 2010
Associate professor, Yokohama city university
 
Oct 2002
 - 
Mar 2005
Postdoctral research associate, Oak Ridge National Laboratory
 
Sep 2002
 - 
Apr 1999
Research associate, Department of advanced materials science, University of Tokyo
 
Mar 1999
 - 
Apr 1999
Research associate, Department of applied physics, University of Tokyo
 

Education

 
Apr 1996
 - 
Feb 1999
Department of applied physics, Faculty of engineering, University of Tokyo
 
Apr 1991
 - 
Mar 1996
Department of applied physics, Faculty of engineering, University of Tokyo
 

Published Papers

 
Shohei Hayashida, Masashige Matsumoto, Masato Hagihala, Nobuyuki Kurita, Hidekazu Tanaka, Shinichi Itoh, Tao Hong, Minoru Soda, Yoshiya Uwatoko, Takatsugu Masuda
SCIENCE ADVANCES   5 eaaw5639-1-eaaw5639-5   Oct 2019   [Refereed]
The investigation of materials that exhibit quantum phase transition provides valuable insights into fundamental problems in physics. We present neutron scattering under pressure in a triangular-lattice antiferromagnet that has a quantum disorder ...
Minoru Soda, Tao Hong, Maxim Avdeev, Hideki Yoshizawa, Takatsugu Masuda, and Hazuki Kawano-Furukawa
Phys. Rev. B   100 144410-1-144410-6   Oct 2019   [Refereed]
Hirotaka Manaka, Hideki Morita, Takuei Akasaka, Yoko Miura, Masato Hagihala, Shohei Hayashida, Minoru Soda, and Takatsugu Masuda
J. Phys. Soc. Jpn.   88 114703-1-114703-13   Oct 2019   [Refereed]
Daichi Hirobe, Masahiro Sato, Masato Hagihala, Yuki Shiomi, Takatsugu Masuda, and Eiji Saitoh
Phys. Rev. Lett.   123 117202-1-117202-7   Sep 2019   [Refereed]
Shinichi Itoh, Tetsuya Yokoo, Takatsugu Masuda, Shinichiro Asai, Hiraku Saito, Daichi Kawana, Ryosuke Sugiura, Toshio Asami, Yoshiaki Ihata
Physica B: Condensed Matter   568 76-80   Sep 2019   [Refereed]
Masashi Hase, Kirrily C. Rule, James R. Hester, Jaime A. Fernandez-Baca, Takatsugu Masuda, and Yukari Matsuo
J. Phys. Soc. Jpn   88 094708-1-094708-5   Aug 2019   [Refereed]
Masato Hagihala, Shohei Hayashida, Maxim Avdeev, Hirotaka Manaka, Hodaka Kikuchi, Takatsugu Masuda
npj Quantum Materials   4 14-1-14-9   Apr 2019   [Refereed]
Shohei Hayashida, Shinichiro Asai, Daiki Kato, Shunsuke Hasegawa, Maxim Avdeev, Huibo Cao, Takatsugu Masuda
Phys. Rev. B   98 224405-1-224405-9   Dec 2018   [Refereed]
We have studied the magnetic order of the rare-earth ferroborate CeFe3(BO3)4
through the thermodynamic and the neutron diffraction measurements. The heat capacity and the magnetic susceptibility revealed antiferromagnetic magnetic ordering at 29 K...
D. Ueta, M. Yoshida, Y. Ikeda, Y. Liu, T. Hong, T. Masuda, H. Yoshizawa
AIP Advances   8 115006-1-115006-5   Oct 2018   [Refereed]
Neutron diffraction experiments have been performed on single crystalline samples of CePtSi3. We found that the incommensurate magnetic propagation vector τ1 = (±0.283, 0, 0) in the phase I (2.2 ∼ 4.8 K) switches to the commensurate vectors τ2 = (...
Naoto Metoki, Hiroki Yamauchi, Hiroyuki S. Suzuki, Hideaki Kitazawa, Masato Hagihara, Takatsugu Masuda, Adam A. Aczel, Songxue Chi, Tao Hong, Masaaki Matsuda, Daniel Pajerowski, and Jaime A. Fernandez-Baca,
J. Phys. Soc. Jpn.   87 094704-1-094704-8   Sep 2018   [Refereed]
The crystalline electric field (CEF) excitation spectra of PrPd5Al2 have been studied by neutron inelastic scattering in order to reveal the f-electron states, where PrPd5Al2 is a Pr-based isostructural compound of the heavy-fermion superconductor...
Minoru Soda, Lieh-Jeng Chang, Masashige Matsumoto, V. Ovidiu Garlea, Bertrand Roessli, Jonathan S. White, Hazuki Kawano-Furukawa, and Takatsugu Masuda
Phys. Rev. B   97 214437-1-214437-6   Jun 2018   [Refereed]
Magnetic excitations in the multiferroic Ba2CoGe2O7 are measured by combination of unpolarized and polarized neutron-scattering techniques. The unpolarized neutron spectrum reveals an anisotropic Q dependence of the intensity of the electromagnon ...
Sazonov Andrew, Hutanu Vladimir, Meven Martin, Roth Georg, Georgii Robert, Masuda Takatsugu, Nafradi Balint
INORGANIC CHEMISTRY   57(9) 5089-5095   May 2018   [Refereed]
For a symmetry-consistent theoretical description of the ferroelectric phase of Ba2MnGe2O7 melilite compound, a precise knowledge of its crystal structure is a prerequisite. Here we report results of single-crystal neutron diffraction experiments ...
Ku S. T., Kumar D., Lees M. R., Lee W-T, Aldus R., Studer A., Imperia P., Asai S., Masuda T., Chen S. W., Chen J. M., Chang L. J.
JOURNAL OF PHYSICS-CONDENSED MATTER   30(15) 155601-1-155601-11   Apr 2018   [Refereed]
We present magnetic susceptibility, heat capacity, and neutron diffraction measurements of polycrystalline Nd2Ru2O7 down to 0.4 K. Three anomalies in the magnetic susceptibility measurements at 146, 21 and 1.8 K are associated with an antiferromag...
Hayashida Shohei, Zaharko Oksana, Kurita Nobuyuki, Tanaka Hidekazu, Hagihala Masato, Soda Minoru, Itoh Shinichi, Uwatoko Yoshiya, Masuda Takatsugu
PHYSICAL REVIEW B   97(14) 140405-1-140405-4   Apr 2018   [Refereed]
We have studied the pressure-induced quantum phase transition in the singlet-ground-state antiferromagnet CsFeCl3. Neutron diffraction experiments under pressure evidence the magnetic long-range order at low temperatures. Magnetic structure analys...
Xie Tao, Gong Dongliang, Ghosh Haranath, Ghosh Abyay, Soda Minoru, Masuda Takatsugu, Itoh Shinichi, Bourdarot Frederic, Regnault Louis-Pierre, Danilkin Sergey, Li Shiliang, Luo Huiqian
PHYSICAL REVIEW LETTERS   120(13) 137001-1-137001-7   Mar 2018   [Refereed]
We use inelastic neutron scattering to study the low-energy spin excitations of the 112-type iron pnictide Ca0.82La0.18Fe0.96Ni0.04As2 with bulk superconductivity below Tc=22  K. A two-dimensional spin resonance mode is found around E=11  meV, whe...
Hayashida Shohei, Ishikawa Hajime, Okamoto Yoshihiko, Okubo Tsuyoshi, Hiroi Zenji, Avdeev Maxim, Manuel Pascal, Hagihala Masato, Soda Minoru, Masuda Takatsugu
PHYSICAL REVIEW B   97(5) 054411-1-054411-7   Feb 2018   [Refereed]
We haved studied the ground state of the classical kagome antiferromagnet NaBa2Mn3F11. Strong magnetic Bragg peaks observed for d spacings shorter than 6.0 Å were indexed by the propagation vector of k0=(0,0,0). Additional peaks with weak intensit...
Itoh Shinichi, Yokoo Tetsuya, Masuda Takatsugu, Yoshizawa Hideki, Soda Minoru, Ibuka Soshi, Ikeda Yoichi, Yoshida Masahiro, Hawai Takafumi, Kawana Daichi, Sugiura Ryosuke, Asami Toshio, Kawamura Yoshihisa, Shinozaki Tomoko, Ihata Yoshiaki
PROCEEDINGS OF THE JOINT CONFERENCE ON QUASIELASTIC NEUTRON SCATTERING AND THE WORKSHOP ON INELASTIC NEUTRON SPECTROMETERS (QENS/WINS 2016): PROBING NANOSCALE DYNAMICS IN ENERGY RELATED MATERIALS   1969 050002-1-050002-5   May 2018   [Refereed]
The High Resolution Chopper Spectrometer (HRC) installed at MLF, J-PARC provides opportunities for dynamical studies of materials over a wide energy-momentum space with high resolution. Three types of inelastic neutron scattering experiments can b...
22ND MEETING OF THE INTERNATIONAL COLLABORATION ON ADVANCED NEUTRON SOURCES (ICANS XXII)   1021    2018   [Refereed]
Shinichi Itoh, Tetsuya Yokoo, Takatsugu Masuda, Hideki Yoshizawa, Minoru Soda, Masahiro Yoshida, Takafumi Hawai, Daichi Kawana, Ryosuke Sugiura, Toshio Asami, and Yoshiaki Ihata
Journal of Physics: Conference Series   1021 012028-1-012028-4   2018   [Refereed]
Neutron Brillouin scattering (NBS) experiments can be performed on the High Resolution Chopper Spectrometer (HRC). Recently, an intensity gain of a factor 2.4 with an improved resolution for NBS has been obtained by improving the detector system, ...
Asai Shinichiro, Soda Minoru, Kasatani Kazuhiro, Ono Toshio, Garlea V. Ovidiu, Winn Barry, Masuda Takatsugu
PHYSICAL REVIEW B   96(10) 104414-1-104414-6   Sep 2017   [Refereed]
We carried out inelastic neutron scattering experiments on a buckled honeycomb lattice antiferromagnet Ba2NiTeO6 exhibiting a stripe structure at a low temperature. Magnetic excitations are observed in the energy range of ℏω≲10 meV having an aniso...
Babkevich P., Shaik N. E., Lancon D., Kikkawa A., Enderle M., Ewings R. A., Walker H. C., Adroja D. T., Manuel P., Khalyavin D. D., Taguchi Y., Tokura Y., Soda M., Masuda T., Ronnow H. M.
PHYSICAL REVIEW B   96(1) 014410-1-014410-12   Jul 2017   [Refereed]
We report detailed neutron scattering studies on Ba2Cu3O4Cl2. The compound consists of two interpenetrating sublattices of Cu, labeled as CuA and CuB, each of which forms a square-lattice Heisenberg antiferromagnet. The two sublattices order at di...
Soda Minoru, Hayashida Shohei, Yoshida Toshiya, Akaki Mitsuru, Hagiwara Masayuki, Avdeev Maxim, Zaharko Oksana, Masuda Takatsugu
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   86(6) 064703-1-064703-5   Jun 2017   [Refereed]
The magnetic structure of the multiferroic Ca2CoSi2O7 was determined by neutron diffraction techniques. A combination of experiments on polycrystalline and single-crystal samples revealed a collinear antiferromagnetic structure with the easy axis ...
Su Yu, Tsujimoto Yoshihiro, Miura Akira, Asai Shinichiro, Avdeev Maxim, Ogino Hiraku, Ako Miho, Belik Alexei A., Masuda Takatsugu, Uchikoshi Tetsuo, Yamaura Kazunari
CHEMICAL COMMUNICATIONS   53(27) 3826-3829   Apr 2017   [Refereed]
A new square-planar zinc oxyhalide, Sr2ZnO2Cl2, was successfully synthesized using a high-pressure method. Absorption spectroscopy revealed an indirect band gap of 3.66 eV. Electronic structure calculations indicated a strong hybridization between...
Kim Jeong-Hwan, Eguchi Haruki, Umemura Masanari, Sato Itaru, Yamada Shigeki, Hoshino Yujiro, Masuda Takatsugu, Aoki Ichio, Sakurai Kazuo, Yamamoto Masahiro, Ishikawa Yoshihiro
NPG ASIA MATERIALS   9 e367-1-e367-14   Mar 2017   [Refereed]
Nanoparticulate agents for magnetic drug delivery systems (DDSs) have extensive applications in targeted drug delivery, contrast imaging and therapeutics. However, no simple synthetic method for magnetic DDS agents has been developed without the n...
Simutis G., Gvasaliya S., Beesetty N. S., Yoshida T., Robert J., Petit S., Kolesnikov A. I., Stone M. B., Bourdarot F., Walker H. C., Adroja D. T., Sobolev O., Hess C., Masuda T., Revcolevschi A., Buechner B., Zheludev A.
PHYSICAL REVIEW B   95(5) 054409-1-054409-6   Feb 2017   [Refereed]
The low-energy magnetic excitation spectrum of the Heisenberg antiferromagnetic S=1/2 chain system Sr2CuO3 with Ni and Ca impurities is studied by neutron spectroscopy. In all cases, a defect-induced spectral pseudogap is observed and shown to sca...
Ohtake Makoto, Umemura Masanari, Sato Itaru, Akimoto Taisuke, Oda Kayoko, Nagasako Akane, Kim Jeong-Hwan, Fujita Takayuki, Yokoyama Utako, Nakayama Tomohiro, Hoshino Yujiro, Ishiba Mai, Tokura Susumu, Hara Masakazu, Muramoto Tomoya, Yamada Sotoshi, Masuda Takatsugu, Aoki Ichio, Takemura Yasushi, Murata Hidetoshi, Eguchi Haruki, Kawahara Nobutaka, Ishikawa Yoshihiro
SCIENTIFIC REPORTS   7 42783-1-42783-12   Feb 2017   [Refereed]
We previously reported that μ-oxo N,N’-bis(salicylidene)ethylenediamine iron [Fe(Salen)], a magnetic organic compound, has direct anti-tumor activity, and generates heat in an alternating magnetic field (AMF). We showed that Fe(Salen) nanoparticle...
T. Haku, M. Soda, M. Sera, K. Kimura, J. Taylor, S. Itoh, T. Yokoo, Y. Matsumoto, D. Yu, R. A. Mole, T. Takeuchi, S. Nakatsuji, Y. Kono, T. Sakakibara, L.-J. Chang, and T. Masuda
8TH INTERNATIONAL CONFERENCE ON HIGHLY FRUSTRATED MAGNETISM 2016   828 012018-1-012018-5   2017   [Refereed]
Inelastic neutron scattering (INS) study on breathing pyrochlore antiferromagnet Ba3Yb2Zn5O11 is presented. Observed crystalline electric field (CEF) excitations are explained by a Hamiltonian of Kramers ion Yb3+ of which the local symmetry exhibi...
S. Asai, T. Oyama, M. Soda, K. Rule, K. Nawa, Z. Hiroi, and T. Masuda
8TH INTERNATIONAL CONFERENCE ON HIGHLY FRUSTRATED MAGNETISM 2016   828 012006-1-012006-5   2017   [Refereed]
We carried out powder neutron diffraction measurements in NaCuMoO4(OD) in order to investigate the ground state of this material. We observe no temperature dependence between the powder neutron diffraction profiles at T = 1.2 and 0.07 K within the...
Minoru Soda and Takatsugu Masuda
8TH INTERNATIONAL CONFERENCE ON HIGHLY FRUSTRATED MAGNETISM 2016   828 012001-1-012001-3   2017   [Refereed]
Dielectric permittivity and nuclear diffuse scattering were measured on a single crystal of relaxor magnet LuFeCoO4 having the triangular lattice. The dielectric constant with the electric field applied in the c-plane is much larger than that with...
Soda Minoru, Hayashida Shohei, Roessli Bertrand, Mansson Martin, White Jonathan S., Matsumoto Masashige, Shiina Ryousuke, Masuda Takatsugu
PHYSICAL REVIEW B   94(9) 094418-1-094418-7   Sep 2016   [Refereed]
Ba2CoGe2O7 exhibits a collinear-antiferromagnetic structure with the easy axis along ⟨100⟩ directions and an antiferroelectric order with the polarization axis along the [001] direction. By applying the electric field the magnetic moment rotates f...
Haku T., Kimura K., Matsumoto Y., Soda M., Sera M., Yu D., Mole R. A., Takeuchi T., Nakatsuji S., Kono Y., Sakakibara T., Chang L. -J., Masuda T.
PHYSICAL REVIEW B   93(22) 220407-1-220407-5   Jun 2016   [Refereed]
We study low-energy excitations in the quantum breathing pyrochlore antiferromagnet Ba3Yb2Zn5O11 by a combination of inelastic neutron scattering (INS) and thermodynamical property measurements. The INS spectra are quantitatively explained by spin...
Soda Minoru, Masuda Takatsugu
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   85(3) 034713-1-034713-5   Mar 2016   [Refereed]
Dielectric and magnetic properties in the relaxor magnet LuFeCoO4 having a triangular lattice are studied by permittivity, magnetization, and neutron diffraction measurements. We found that LuFeCoO4 has the nuclear diffuse scattering induced by Po...
Soda Minoru, Honma Yuki, Takamizawa Satoshi, Ohira-Kawamura Seiko, Nakajima Kenji, Masuda Takatsugu
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   85(3) 034717-1-034717-9   Mar 2016   [Refereed]
Inelastic neutron scattering experiments are performed on the nanoporous metal complex Cu-trans-1,4-cyclohexanedicarboxylic acid (Cu-CHD) adsorbing O2 molecules to identify the spin model of the O2-based magnet realized in the host complex. It is ...
Haku Tendai, Soda Minoru, Sera Masakazu, Kimura Kenta, Itoh Shinichi, Yokoo Tetsuya, Masuda Takatsugu
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   85(3) 034721-1-034721-5   Mar 2016   [Refereed]
Inelastic neutron scattering measurement is performed on the breathing pyrochlore antiferromagnet Ba3Yb2Zn5O11. The observed dispersionless excitations are explained on the basis of a crystalline electric field (CEF) Hamiltonian of the Kramers ion...
Asai Shinichiro, Soda Minoru, Kasatani Kazuhiro, Ono Toshio, Avdeev Maxim, Masuda Takatsugu
PHYSICAL REVIEW B   93(2) 024412-1-024412-7   Jan 2016   [Refereed]
We investigate the magnetic order of the buckled honeycomb lattice antiferromagnet Ba2NiTeO6 and its related antiferromagnet Ba3NiTa2O9 by neutron diffraction measurements. We observe magnetic Bragg peaks below the transition temperatures, and ide...
S. Hayashida, M. Soda, S. Itoh, T. Yokoo, K. Ohgushi, D. Kawana, and T. Masuda
VI EUROPEAN CONFERENCE ON NEUTRON SCATTERING (ECNS2015)   746 012059-1-012059-5   2016   [Refereed]
We performed inelastic neutron scattering experiments on a multiferroic material NdFe3(BO3)4 to explore the crystal field excitations, where the magnetic anisotropy of the Nd3+ crystal field was responsible for the multiferroicity. Flat modes were...
Hayashida S., Soda M., Itoh S., Yokoo T., Ohgushi K., Kawana D., Ronnow H. M., Masuda T.
PHYSICAL REVIEW B   92(5) 054402-1-054402-9   Aug 2015   [Refereed]
We performed inelastic neutron scattering measurements on single crystals of NdFe3(11BO3)4 to explore the magnetic excitations, to establish the underlying Hamiltonian, and to reveal the detailed nature of hybridization between the 4f and 3d magne...
Nilsen Goran. J., Okamoto Yoshihiko, Masuda Takatsugu, Rodriguez-Carvajal Juan, Mutka Hannu, Hansen Thomas, Hiroi Zenji
PHYSICAL REVIEW B   91(17) 174435-1-174435-8   May 2015   [Refereed]
We present a neutron scattering study of the chromate spinel LiInCr4O8, which realizes a “breathing” pyrochlore lattice of S=32 spins. High-resolution neutron diffraction reveals a phase separation into a mixture of minority cubic and majority tet...
Eguchi Haruki, Umemura Masanari, Kurotani Reiko, Fukumura Hidenobu, Sato Itaru, Kim Jeong-Hwan, Hoshino Yujiro, Lee Jin, Amemiya Naoyuki, Sato Motohiko, Hirata Kunio, Singh David J., Masuda Takatsugu, Yamamoto Masahiro, Urano Tsutomu, Yoshida Keiichiro, Tanigaki Katsumi, Yamamoto Masaki, Sato Mamoru, Inoue Seiichi, Aoki Ichio, Ishikawa Yoshihiro
SCIENTIFIC REPORTS   5 9194-1-9194-14   Mar 2015   [Refereed]
Research on controlled drug delivery for cancer chemotherapy has focused mainly on ways to deliver existing anti-cancer drug compounds to specified targets, e.g., by conjugating them with magnetic particles or encapsulating them in micelles. Here,...
Hayashida Shohei, Soda Minoru, Itoh Shinichi, Yokoo Tetsuya, Ohgushi Kenya, Kawana Daichi, Masuda Takatsugu
20TH INTERNATIONAL CONFERENCE ON MAGNETISM, ICM 2015   75 127-133   Dec 2015   [Refereed]
nelastic neutron scattering experiment is performed on single crystals of multiferroics NdFe3(11BO3)4 to explore the magnetic excitations. Fe-centered dispersive excitation with the band width of 5 meV is observed along the crystallographic c∗ dir...
Manaka Hirotaka, Hagihala Masato, Hayashida Shohei, Soda Minoru, Masuda Takatsugu, Miura Yoko
20TH INTERNATIONAL CONFERENCE ON MAGNETISM, ICM 2015   75 718-725   Dec 2015   [Refereed]
In this study, the temperature (T) dependence of specific heat (Cp) is investigated in an equilateral triangular spin tube CsCrF4 above T = 0.38K under several magnetic fields (B). At B = 0 T, no λ-type anomaly of the temperature dependence [Cp(T)...
Thede M., Haku T., Masuda T., Baines C., Pomjakushina E., Dhalenne G., Revcolevschi A., Morenzoni E., Zheludev A.
PHYSICAL REVIEW B   90(14) 144407-1-144407-8   Oct 2014   [Refereed]
Long-range magnetic ordering in the quasi-one-dimensional random-bond antiferromagnet BaCu2(Si1−xGex)2O7 is studied in muon spin rotation experiments as a function of disorder strength. Compared to the disorder-free parent materials, the saturatio...
Hase Masashi, Soda Minoru, Masuda Takatsugu, Kawana Daichi, Yokoo Tetsuya, Itoh Shinichi, Matsuo Akira, Kindo Koichi, Kohno Masanori
PHYSICAL REVIEW B   90(2) 024416-1-024416-7   Jul 2014   [Refereed]
A spin-singlet ground state with a spin gap has been discovered in antiferromagnetic spin chain substances when the spin value is 1/2, 1, or 2. To find spin-gap (singlet-triplet) excitations in spin-32 chain substances, we performed inelastic neut...
Soda M., Matsumoto M., Mansson M., Ohira-Kawamura S., Nakajima K., Shiina R., Masuda T.
PHYSICAL REVIEW LETTERS   112(12) 127205-1-127205-5   Mar 2014   [Refereed]
We demonstrate the existence of the spin-nematic interactions in an easy-plane type antiferromagnet Ba2CoGe2O7 by exploring the magnetic anisotropy and spin dynamics. The combination of neutron scattering and magnetic susceptibility measurements r...
Masashige Matsumoto, Minoru Soda, and Takatsugu Masuda
JPS Conference Proceeding   3 014033-1-014033-6   2014   [Refereed]
It is know that a paramagnetic phase is stabilized in integer spin systems with large easy-plane type single-ion anisotropy owing to the local singlet groundstate. In this case, applying pressure can collapse the excitation gap and induce a quantu...
Y. Yasui, R. Okazaki, I. Terasaki, M. Hase, M. Hagihala, T. Masuda and T. Sakakibara
JPS Conference Proceeding   3 014014-1-014014-6   2014   [Refereed]
Magnetic properties at low temperature down to 0.06 K and high magnetic field up to 14.5 T have been studied for polycrystalline samples of Rb2Cu2Mo3O12 with quasi-one dimensional spin 1/2 Cu2+ chains formed of edge-sharing CuO4 square planes so c...
Matsumoto Masashige, Soda Minoru, Masuda Takatsugu
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   82(9) 093703-1-093703-5   Sep 2013   [Refereed]
In integer spin systems with a strong easy-plane type single-ion anisotropy, a paramagnetic ground state is stabilized with a finite excitation gap. Applying a magnetic field or pressure can collapse the excitation gap and induce quantum phase tra...
Kikuchi Jun, Nagura Shiro, Murakami Kazumasa, Masuda Takatsugu, Redhammer Guenther J.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   82(3) 034710-1-034710-10   Mar 2013   [Refereed]
Nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) of Cu have been measured in a coupled spin dimers and chains compound Cu2Fe2Ge4O13. Cu NQR has also been measured in an isostructural material Cu2Sc2Ge4O13 including only spin...
Itoh Shinichi, Yokoo Tetsuya, Kawana Daichi, Yoshizawa Hideki, Masuda Takatsugu, Soda Minoru, Sato Taku J., Satoh Setsuo, Sakaguchi Masataka, Muto Suguru
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   82 SA033-1-SA033-6   Jan 2013   [Refereed]
The High Resolution Chopper Spectrometer (HRC) was installed at J-PARC, to study dynamics in condensed matters with high-resolutions and relatively-high-energy neutrons. Although the HRC was damaged by the earthquake disaster, we recovered and sta...
Masuda Takatsugu, Hagihala Masato, Kondoh Yosuke, Kaneko Koji, Metoki Naoto
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   80(11) 113705-1-113705-4   Nov 2011   [Refereed]
We study a field-induced quantum phase in the weakly-coupled ferromagnetic frustrated chain LiCuVO 4 by a neutron diffraction technique. A new incommensurate magnetic peak is observed at H ≥8.5 T. The field-dependent propagation vector is identifi...
Matsumoto Masashige, Kuroe Haruhiko, Sekine Tomoyuki, Masuda Takatsugu
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   79(8) 084703-1-084703-18   Aug 2010   [Refereed]
Magnetic excitation in coupled multispin system is studied theoretically focusing on Cu 2 Fe 2 Ge 4 O 13 and Cu 2 CdB 2 O 6 as typical examples of such system. These compounds consist of spin dimer and spin monomer parts and show an antiferromagne...
Masuda T., Kitaoka S., Takamizawa S., Metoki N., Kaneko K., Rule K. C., Kiefer K., Manaka H., Nojiri H.
PHYSICAL REVIEW B   81(10) 100402-1-100402-4   Mar 2010   [Refereed]
Spin dynamics of the square lattice Heisenberg antiferromagnet, Ba2MnGe2O7, is studied by a combination of bulk measurements, neutron diffraction, and inelastic neutron-scattering techniques. Easy plane type antiferromagnetic order is identified a...
Kikuchi J., Nagura S., Nakanishi H., Masuda T.
INTERNATIONAL CONFERENCE ON MAGNETISM (ICM 2009)   200 022024-1-022024-4   2010   [Refereed]
We report on the results of nuclear magnetic and quadrupole resonances of Cu in Cu2Fe2Ge4O13 consisting of weakly coupled Cu dimers and Fe chains. In the antiferromagnetic state below 39 K, we observed nuclear resonance of Cu under the internal ma...
Matsumoto Masashige, Kuroe Haruhiko, Sekine Tomoyuki, Masuda Takatsugu
INTERNATIONAL CONFERENCE ON MAGNETISM (ICM 2009)   200 022034-1-022034-4   2010   [Refereed]
Cu2Fe2Ge4O13 is a quantum magnet consisting of Cu spin dimers and Fe spin chains. It shows an antiferromagnetic phase transition at low temperatures due to the magnetic moment of Fe. Since the two parts are weakly coupled, magnetic excitations are...
Masuda T., Kakurai K., Zheludev A.
PHYSICAL REVIEW B   80(18) 180412-1-180412-4   Nov 2009   [Refereed]
We study S=1/2 dimer excitation in a coupled chain and dimer compound Cu2Fe2Ge4O13 by inelastic neutron-scattering technique. The Zeeman split of the dimer triplet by a staggered field is observed at low temperature. With the increase in temperatu...
Masuda Takatsugu
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   600(1) 232-236   Feb 2009   [Refereed]
Cu2Fe2Ge4O13 is known as a weakly coupled quantum dimers and classical chains compound with separated energy scale. Simulation of time of flight experiment on this compound is performed under a conventional resolution condition of AMATERAS spectro...
Kimura S., Matsuda M., Masuda T., Hondo S., Kaneko K., Metoki N., Hagiwara M., Takeuchi T., Okunishi K., He Z., Kindo K., Taniyama T., Itoh M.
PHYSICAL REVIEW LETTERS   101(20) 207201-1-207201-4   Nov 2008   [Refereed]
From neutron diffraction measurements on a quasi-1D Ising-like Co2+ spin compound BaCo2V2O8, we observed an appearance of a novel type of incommensurate ordering in magnetic fields. This ordering is essentially different from the Néel-type orderin...
Sekine Tomoyuki, Kaneko Tomomi, Kuroe Haruhiko, Masuda Takatsugu
PHYSICAL REVIEW B   78(13) 134409-1-134409-10   Oct 2008   [Refereed]
By means of Raman scattering we have studied the spin-Peierls (SP) transition in Ni-doped CuGeO3 crystals. The folded-phonon peak extremely broadens and the two-magnetic-excitation mode disappears when the Ni concentration is above about 2.0%, ind...
Zheludev A., Garlea V. O., Masuda T., Manaka H., Regnault L.-P., Ressouche E., Grenier B., Chung J.-H., Qiu Y., Habicht K., Kiefer K., Boehm M.
PHYSICAL REVIEW B   76(5) 054450-1-054450-10   Aug 2007   [Refereed]
Inelastic and elastic neutron scattering is used to study spin correlations in the quasi-one-dimensional quantum antiferromagnet IPA−CuCl3 in strong applied magnetic fields. A condensation of magnons and commensurate transverse long-range ordering...
Masuda Takatsugu, Takamizawa Satoshi, Hirota Kazuma, Ohba Masaaki, Kitagawa Susumu
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   77(8) 083703-1-083703-4   Aug 2008   [Refereed]
We performed an inelastic neutron scattering experiment to study the magnetic excitation of O 2 molecules adsorbed in a microporous compound. A dispersionless excitation with characteristic intensity modulation is observed at ℏω=7.8 meV at low tem...
Manaka Hirotaka, Miyashita Yusuke, Watanabe Yusuke, Masuda Takatsugu
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   76(8) 085003-1-085003-2   Aug 2007   [Refereed]
Masuda T., Kakurai K., Matsuda M., Kaneko K., Metoki N.
PHYSICAL REVIEW B   75(22) 220401-1-220401-4   Jun 2007   [Refereed]
Cu2Fe2Ge4O13 is a bicomponent compound that consists of Cu dimers and Fe chains with separate energy scale. By inelastic neutron scattering technique with high-energy resolution we observed the indirect Fe-Fe exchange coupling by way of the Cu dim...
Garlea V. O., Zheludev A., Masuda T., Manaka H., Regnault L.-P., Ressouche E., Grenier B., Chung J.-H., Qiu Y., Habicht K., Kiefer K., Boehm M.
PHYSICAL REVIEW LETTERS   98(16) 167202-1-167202-4   Apr 2007   [Refereed]
The weakly coupled quasi-one-dimensional spin ladder compound (CH3)2CHNH3CuCl3 is studied by neutron scattering in magnetic fields exceeding the critical field of Bose-Einstein condensation of magnons. Commensurate long-range order and the associa...
Manaka Hirotaka, Miyashita Yusuke, Watanabe Yusuke, Masuda Takatsugu
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   76(4) 044710-1-044710-3   Apr 2007   [Refereed]
We synthesized a single-phase polycrystalline sample of a double-layer perovskite fluoride K 3 Cu 2 F 7 . This compound is the new member of the potassium copper fluoride family, which has an antiferrodistortive orbital order (AFDOO). Magnetic sus...
Zheludev A., Masuda T., Dhalenne G., Revcolevschi A., Frost C., Perring T.
PHYSICAL REVIEW B   75(5) 054409-1-054409-5   Feb 2007   [Refereed]
The magnetic dynamic structure factor of the one-dimensional S=1∕2 chain system BaCu2(Si0.5Ge0.5)2O7 is studied in a wide range of energy transfers and temperatures. Contrary to previous erroneous reports [T. Masuda et al., Phys. Rev. Lett. 93, 07...
Masuda T., Redhammer G. J.
PHYSICAL REVIEW B   74(5) 054418-1-054418-4   Aug 2006   [Refereed]
The compound Cu2Sc2Ge4O13 is presented as a member of the family of weakly coupled spin chain and dimer compounds Cu2M2Ge4O13. Magnetic susceptibility, heat capacity, and neutron inelastic-scattering measurements reveal that the compound has the s...
Masuda T, Zheludev A, Manaka H, Regnault LP, Chung JH, Qiu Y
PHYSICAL REVIEW LETTERS   96(4) 047210-1-047210-4   Feb 2006   [Refereed]
Magnetic excitations in the quasi-one-dimensional antiferromagnet IPA-CuCl3 are studied by cold neutron inelastic scattering. Strongly dispersive gap excitations are observed. Contrary to previously proposed models, the system is best described as...
Masuda T., Zheludev A., Manaka H., Chung J. -H.
LOW TEMPERATURE PHYSICS, PTS A AND B   850 1031-1032   Dec 2006   [Refereed]
The spin gap material IPA‐CuCl3 has been extensively studied as a ferromagnetic‐antiferromagnetic bond‐alternating S = 1/2 chain. This description of the system was derived from structural considerations and bulk measurements. New inelastic neutro...
Masuda T, Zheludev A, Sales B, Imai S, Uchinokura K, Park S
PHYSICAL REVIEW B   72(9) 094434-1-094434-8   Sep 2005   [Refereed]
Magnetic excitations in a weakly coupled spin dimers and chains compound Cu2Fe2Ge4O13 are measured by inelastic neutron scattering. Both structure factors and dispersion of low-energy excitations up to 10meV energy transfer are well described by a...
Masuda T, Zheludev A, Roessli B, Bush A, Markina M, Vasiliev A
PHYSICAL REVIEW B   72(1) 014405-1-014405-7   Jul 2005   [Refereed]
The quasi-one-dimensional helimagnet LiCu2O2 was studied by single crystal inelastic neutron scattering. The dispersion relation of spin wave excitations was measured in the vicinity of the principal magnetic Bragg reflection. A spin wave theoreti...
Masuda T, Zheludev A, Sales B, Imai S, Uchinokura K
PROGRESS OF THEORETICAL PHYSICS SUPPLEMENT   159 96-100   May 2005   [Refereed]
Magnetic excitations in the cooperative ordered state in a weakly coupled Fe chains and Cu dimers compound Cu2Fe2Ge4O13 is studied by thermal neutron scattering technique. We show that the low energy excitations up to 10 meV in wide q range are we...
Glazkov VN, Smirnov AI, von Nidda HAK, Loidl A, Uchinokura K, Masuda T
PHYSICAL REVIEW LETTERS   94(5) 057205-1-057205-4   Feb 2005   [Refereed]
The paramagnetic fraction surviving at the impurity-induced antiferromagnetic phase transition in the spin-Peierls magnet CuGeO3 is found to increase with an external magnetic field. This effect is explained by the competition of the Zeeman intera...
Masuda T, Zheludev A, Bush A, Markina M, Vasiliev A
PHYSICAL REVIEW LETTERS   94(3) 039706-1-039706-1   Jan 2005   [Refereed]
A Reply to the Comment by S.-L. Drechsler et al.
Masuda T, Zheludev A, Grenier B, Imai S, Uchinokura K, Ressouche E, Park S
PHYSICAL REVIEW LETTERS   93(7) 077202-1-077202-4   Aug 2004   [Refereed]
The unusual magnetic properties of a novel low-dimensional quantum ferrimagnet Cu2Fe2Ge4O13 are studied using bulk methods, neutron diffraction, and inelastic neutron scattering. It is shown that this material can be described in terms of two low-...
Masuda T, Zheludev A, Uchinokura K, Chung JH, Park S
PHYSICAL REVIEW LETTERS   93(7) 077206-1-077206-4   Aug 2004   [Refereed]
Single crystal inelastic neutron scattering is used to study dynamic spin correlations in the quasi-one-dimensional quantum antiferromagnet BaCu2(Si0.5Ge0.5)2O7, where the exchange constant fluctuates due to a random distribution of Si and Ge atom...
Glazkov V. N., Smirnov A. I., von Nidda H. -A. Krug, Loidl A., Masuda T., Uchinokura K.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   272 E695-E696   May 2004   [Refereed]
A detailed ESR study of the microscopic phase separation occuring at the impurity-induced magnetic ordering in the diluted CuGeO3 is performed. A dependence of the paramagnetic fraction below the transition temperature on the applied magnetic fiel...
Masuda T, Zheludev A, Bush A, Markina M, Vasiliev A
PHYSICAL REVIEW LETTERS   92(17) 177201-1-177201-4   Apr 2004   [Refereed]
Neutron diffraction and bulk measurements are used to determine the nature of the low-temperature ordered state in LiCu2O2, a S=1/2 spin-chain compound with competing interactions. The spin structure is found to be helimagnetic, with a propagation...
Zheludev A, Masuda T, Sales B, Mandrus D, Papenbrock T, Barnes T, Park S
PHYSICAL REVIEW B   69(14) 144417-1-144417-9   Apr 2004   [Refereed]
The quasi-one-dimensional bond-alternating S=1 quantum antiferromagnet [Ni(N,N′−bis(3aminopropyl)propane−1,3−diamine(μ−NO2)]ClO4 (NTENP) is studied by single-crystal inelastic neutron scattering. Parameters of the measured dispersion relation for ...
Masuda T, Chakoumakos BC, Nygren CL, Imai S, Uchinokura K
JOURNAL OF SOLID STATE CHEMISTRY   176(1) 175-179   Nov 2003   [Refereed]
The structure of Cu2Fe2Ge4O13, previously thought to be CuFeGe2O6, has been determined from single-crystal X-ray diffraction data to be monoclinic, P21/m, a=12.1050(6), b=8.5073(4), c=4.8736(2) Å, β=96.145(1)°, Z=2, with R1=0.0231 and wR2=0.0605. ...
Bertaina S, Pashchenko VA, Stepanov A, Masuda T, Uchinokura K
PHYSICAL REVIEW LETTERS   92(5) 057203-1-057203-4   Feb 2004   [Refereed]
We have investigated the electron spin resonance (ESR) on single crystals of BaCu2Ge2O7 at temperatures between 300 and 2 K and in a large frequency band, 9.6–134 GHz, in order to test the predictions of a recent theory, proposed by Oshikawa and A...
Tanokura Y, Oono Y, Ikeda S, Kuroe H, Sekine T, Masuda T, Uchinokura K
PHYSICAL REVIEW B   68(5) 054412-1-054412-10   Aug 2003   [Refereed]
By means of Raman scattering we have observed the appearance of the folded phonon modes and the two-magnetic-excitation bound state under high pressures in 3.5% Mg-doped CuGeO3 crystals. The spin-Peierls (SP) gap mode is also observed. These facts...
Masuda T, Zheludev A, Kageyama H, Vasiliev AN
EUROPHYSICS LETTERS   63(5) 757-763   Sep 2003   [Refereed]
A new spin-ladder family material BiCu2VO6 is studied by means of magnetic susceptibility, heat capacity and neutron inelastic-scattering measurements on a powder sample. Singlet ground state and finite spin-gap are confirmed by thermal-activated–...
Zheludev A, Sato T, Masuda T, Uchinokura K, Shirane G
PHYSICAL REVIEW B   68(2) 024428-1-024428-5   Jul 2003   [Refereed]
The square-lattice antiferromagnet Ba2CoGe2O7 is studied by means of neutron diffraction and inelastic scattering. This material is isostructural to the well-known Dzyaloshinskii-Moriya helimagnet Ba2CuGe2O7 but exhibits commensurate long-range Né...
Wang YJ, Kim YJ, Christianson RJ, LaMarra SC, Chou FC, Masuda T, Tsukada I, Uchinokura K, Birgeneau RJ
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   72(6) 1544-1553   Jun 2003   [Refereed]
We report comprehensive synchrotron x-ray scattering and magnetic susceptibility studies of the doped spin–Peierls materials Cu 1- x Zn x GeO 3 and CuGe 1- y Si y O 3 . Temperature versus dopant concentration phase diagrams are mapped out for both...
Tsukada I, Takeya J, Masuda T, Uchinokura K, Zheludev A
PHYSICA B-CONDENSED MATTER   329 886-887   May 2003   [Refereed]
Anomalous two-stage spin-flop transition in BaCu2Si2O7 was investigated in detail. This compound shows antiferromagnetic long-range order below T-N = 9.2 K with its c-axis as a spin easy axis. Magnetic field applied to the c direction induces spin...
Zheludev A, Raymond S, Regnault LP, Essler FHL, Kakurai K, Masuda T, Uchinokura K
PHYSICAL REVIEW B   67(13) 134406-1-134406-10   Apr 2003   [Refereed]
The polarization dependence of magnetic excitations in the quasi-one-dimensional antiferromagnet BaCu2Si2O7 is studied as a function of momentum and energy transfer. The results of inelastic neutron-scattering measurements are directly compared to...
Masuda T, Yano D, Kuroda R, Uchinokura K, Kuroe H, Sekine T, Katsuki Y, Ohwada K, Fujii Y, Nakao H, Murakami Y
PHYSICAL REVIEW B   67(2) 024423-1-024423-6   Jan 2003   [Refereed]
The effect of pressure is studied on highly Mg-doped CuGeO3, which at ambient pressure shows an antiferromagnetic transition but no spin-Peierls transition. The magnetic susceptibility under pressure was measured; the broad maximum around 60 K shi...
Tanokura Y, Oono Y, Kuroe H, Sekine T, Masuda T, Uchinokura K
PHYSICA B-CONDENSED MATTER   329 882-883   May 2003   [Refereed]
Raman-scattering study has been carried out in 3.5% Mg-doped CuGeO3 crystals under high pressures at low temperatures. This sample does not undertake the spin-Peierls (SP) transition at ambient pressure. The folded phonon modes and the two-magneti...
Hayn R, Pashchenko VA, Stepanov A, Masuda T, Uchinokura K
PHYSICAL REVIEW B   66(18) 184414-1-184414-5   Nov 2002   [Refereed]
Antiferromagnetic resonance (AFMR) of BaCu2Si2O7 and a microscopic theory for the magnetic anisotropy of spin-1/2 chain compounds with folded CuO3 geometry being in good agreement with the available data are presented. The AFMR studies at 4.2 K sh...
Masuda T, Sakaguchi T, Uchinokura K
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   71(11) 2637-2639   Nov 2002   [Refereed]
The magnetism of a new quantum-spin material NaV(WO 4 ) 2 is studied. The crystal structure shows a zig-zag S =1 spin chain along the c axis. The magnetic susceptibility shows that the material has a spin gap. The exchange interaction and the ener...
Smirnov AI, Glazkov VN, Masuda T, Uchinokura K, Demianets LN, Shapiro AY
PHYSICA B-CONDENSED MATTER   329 699-700   May 2003   [Refereed]
The ESR spectra of spin-Peierls crystal CuGeO3 and Haldane magnet PbNi2V2O8 doped with Mg revealed the coexistence of paramagnetic and antiferromagnetic spin resonance modes below the points of the impurity induced ordering. The ordering is known ...
Sato T, Masuda T, Uchinokura K
PHYSICA B-CONDENSED MATTER   329 880-881   May 2003   [Refereed]
A two-dimensional antiferromagnet (S=3/2), Ba2CoGe2O7, was studied, which is isostructural to S=1/2 spiral antiferromagnet, Ba2CuGe2O7. A single crystal of Ba2CoGe2O7 was grown and its magnetization was measured. A weak ferromagnetism was observed...
Zheludev A, Ressouche E, Tsukada I, Masuda T, Uchinokura K
PHYSICAL REVIEW B   65(17) 174416-1-174416-6   May 2002   [Refereed]
The unusual two-stage spin-flop transition in the quasi-one-dimensional S=1/2 antiferromagnet BaCu2Si2O7 is studied by single-crystal neutron diffraction. The staggered magnetization in the system, aligned along the (0,0,1) direction in zero field...
Fudamoto Y, Gat IM, Larkin MI, Merrin J, Nachumi B, Savici AT, Uemura YJ, Luke GM, Kojima KM, Hase M, Masuda T, Uchinokura K
PHYSICAL REVIEW B   65(17) 174428-1-174428-10   May 2002   [Refereed]
Quasistatic spin freezing is observed at T=7.0K in the muon spin relaxation (μSR) measurements of polycrystalline Cu3WO6. This material has been widely considered to possess a nonmagnetic spin-singlet ground state based on the previous neutron sca...
Christianson RJ, Wang YJ, LaMarra SC, Birgeneau RJ, Kiryukhin V, Masuda T, Tsukada I, Uchinokura K, Keimer B
PHYSICAL REVIEW B   66(17) 174105-1-174105-9   Nov 2002   [Refereed]
We present results of a systematic x-ray scattering study of the effects of Mg doping on the high-field incommensurate phase of CuGeO3. Lorentzian-squared line shapes, the changing of the first-order transition to second order, and the destruction...
Zheludev A, Kenzelmann M, Raymond S, Masuda T, Uchinokura K, Lee SH
PHYSICAL REVIEW B   65(1) 014402-1-014402-9   Nov 2001   [Refereed]
Inelastic neutron scattering is used to identify single-particle and continuum spin excitations in the quasi-one-dimensional S=1/2 antiferromagnet BaCu2Si2O7. In the data analysis, close attention is given to resolution effects. A gap in the conti...
Tsukada I, Takeya J, Masuda T, Uchinokura K
PHYSICAL REVIEW LETTERS   87(12) 127203-1-127203-4   Sep 2001   [Refereed]
Two-stage spin-flop transitions are observed in the quasi-one-dimensional antiferromagnet BaCu2Si2O7. A magnetic field applied along the easy axis induces a spin-flop transition at 2.0 T followed by a second transition at 4.9 T. The magnetic susce...
Takehana K, Takamasu T, Hase M, Kido G, Masuda T, Uchinokura K
PHYSICAL REVIEW B   63(24) 245413-1-245413-6   Jun 2001   [Refereed]
The doping effect of the folded phonon mode at 98cm−1 was investigated on Si-doped CuGeO3 by magneto-optical measurements in the far-infrared region under a high magnetic field. The folded phonon mode at 98cm−1 appears not only in the dimerized ph...
Takeya J, Tsukada I, Ando Y, Masuda T, Uchinokura K, Tanaka I, Feigelson RS, Kapitulnik A
PHYSICAL REVIEW B   63(21) 214407-1-214407-6   Jun 2001   [Refereed]
The thermal conductivity κ of Cu1−xMgxGeO3 is measured in magnetic fields up to 16 T. At the transition field Hc to the high-field incommensurate (I) phase, κ abruptly decreases. While κ of the pure CuGeO3 is enhanced with the application of the h...
Masuda T, Uchinokura K, Hayashi T, Miura N
PHYSICAL REVIEW B   66(17) 174416-1-174416-7   Nov 2002   [Refereed]
The impurity-induced antiferromagnetic phase in Pb(Ni1−xMgx)2V2O8 (x=0.020, 0.010, and 0.0050) is studied by means of heat-capacity and magnetization measurements. One S=1 spin is induced by one nonmagnetic impurity, which contributes to the antif...