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Pardo-Sainz M, Cova F, Rodríguez-Velamazán JA, Puente-Orench I, Kousaka Y, Mito M, Campo J. Revisiting the magnetic structure of Holmium at high pressure by using neutron diffraction. Sci Rep 2023; 13:12168. [PMID: 37500740 PMCID: PMC10374572 DOI: 10.1038/s41598-023-39284-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 07/22/2023] [Indexed: 07/29/2023] Open
Abstract
Low-temperature neutron diffraction experiments at [Formula: see text] GPa have been conducted to investigate the magnetic structures of metallic Holmium at high pressures by employing a long d-spacing high-flux diffractometer and a Paris-Edinburgh press cell inside a cryostat. We find that at [Formula: see text] GPa and [Formula: see text] K, no nuclear symmetry change is observed, keeping therefore the hexagonal closed packed (hcp) symmetry at high pressure. Our neutron diffraction data confirm that the ferromagnetic state does not exist. The magnetic structure corresponding to the helimagnetic order, which survives down to 5 K, is fully described by the magnetic superspace group formalism. These results are consistent with those previously published using magnetization experiments.
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Affiliation(s)
- M Pardo-Sainz
- Instituto de Nanociencia y Materiales de Aragón (CSIC - Universidad de Zaragoza) and Depto. de Física de la Materia Condensada, C/Pedro Cerbuna 12, 50009, Zaragoza, Spain
- Graduate School of Science, Osaka Metropolitan University, 1-1 Gakuencho, Sakai, Osaka, 599-8531, Japan
| | - F Cova
- Instituto de Nanociencia y Materiales de Aragón (CSIC - Universidad de Zaragoza) and Depto. de Física de la Materia Condensada, C/Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | | | - I Puente-Orench
- Instituto de Nanociencia y Materiales de Aragón (CSIC - Universidad de Zaragoza) and Depto. de Física de la Materia Condensada, C/Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Y Kousaka
- Department of Physics and Electronics, Osaka Metropolitan University, 1-1 Gakuencho, Sakai, Osaka, 599-8531, Japan
| | - M Mito
- Graduate School of Engineering, Kyushu Institute of Technology, Kitakyushu, 804-8550, Japan
| | - J Campo
- Instituto de Nanociencia y Materiales de Aragón (CSIC - Universidad de Zaragoza) and Depto. de Física de la Materia Condensada, C/Pedro Cerbuna 12, 50009, Zaragoza, Spain.
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2
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Shimamoto Y, Matsushima Y, Hasegawa T, Kousaka Y, Proskurin I, Kishine J, Ovchinnikov AS, Goncalves FJT, Togawa Y. Observation of Collective Resonance Modes in a Chiral Spin Soliton Lattice with Tunable Magnon Dispersion. Phys Rev Lett 2022; 128:247203. [PMID: 35776483 DOI: 10.1103/physrevlett.128.247203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Accepted: 04/15/2022] [Indexed: 06/15/2023]
Abstract
A chiral spin soliton lattice (CSL), one of the representative systems of a magnetic superstructure, exhibits reconfigurability in periodicity over a macroscopic length scale. Such coherent and tunable characteristics of the CSL lead to an emergence of elementary excitation of the CSL as phononlike modes due to translational symmetry breaking and bring a controllability of the dispersion relation of the CSL phonon. Using a broadband microwave spectroscopy technique, we directly found that higher-order magnetic resonance modes appear in the CSL phase of a chiral helimagnet CrNb_{3}S_{6}, which is ascribed to the CSL phonon response. The resonance frequency of the CSL phonon can be tuned between 16 and 40 GHz in the vicinity of the critical field, where the CSL period alters rapidly. The frequency range of the CSL phonon is expected to extend over 100 GHz as extrapolated on the basis of the theoretical model. The present results indicate that chiral helimagnets could work as materials useful for broadband signal processing in the millimeter-wave band.
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Affiliation(s)
- Y Shimamoto
- Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan
- Department of Physics and Electronics, Osaka Metropolitan University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan
| | - Y Matsushima
- Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan
| | - T Hasegawa
- Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan
| | - Y Kousaka
- Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan
- Department of Physics and Electronics, Osaka Metropolitan University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan
| | - I Proskurin
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
- Institute of Natural Sciences and Mathematics, Ural Federal University, Ekaterinburg 620002, Russia
| | - J Kishine
- Division of Natural and Environmental Sciences, The Open University of Japan, Chiba 261-8586, Japan
- Institute for Molecular Science, Okazaki, Aichi 444-8585, Japan
| | - A S Ovchinnikov
- Institute of Natural Sciences and Mathematics, Ural Federal University, Ekaterinburg 620002, Russia
- Institute of Metal Physics, Ural Division, Russian Academy of Sciences, Ekaterinburg 620219, Russia
| | - F J T Goncalves
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Y Togawa
- Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan
- Department of Physics and Electronics, Osaka Metropolitan University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan
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3
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Honda T, Yamasaki Y, Nakao H, Murakami Y, Ogura T, Kousaka Y, Akimitsu J. Topological metastability supported by thermal fluctuation upon formation of chiral soliton lattice in [Formula: see text]. Sci Rep 2020; 10:18596. [PMID: 33122696 PMCID: PMC7596096 DOI: 10.1038/s41598-020-74945-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 10/07/2020] [Indexed: 11/29/2022] Open
Abstract
Topological magnetic structure possesses topological stability characteristics that make it robust against disturbances which are a big advantage for data processing or storage devices of spintronics; nonetheless, such characteristics have been rarely clarified. This paper focused on the formation of chiral soliton lattice (CSL), a one-dimensional topological magnetic structure, and provides a discussion of its topological stability and influence of thermal fluctuation. Herein, CSL responses against change of temperature and applied magnetic field were investigated via small-angle resonant soft X-ray scattering in chromium niobium sulfide ([Formula: see text]). CSL transformation relative to the applied magnetic field demonstrated a clear agreement with the theoretical prediction of the sine-Gordon model. Further, there were apparent differences in the process of chiral soliton creation and annihilation, discussed from the viewpoint of competing between thermal fluctuation and the topological metastability.
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Affiliation(s)
- T. Honda
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, 305-0801 Japan
| | - Y. Yamasaki
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, 305-0801 Japan
- Research and Services Division of Materials Data and Integrated System (MaDIS), National Institute for Materials Science (NIMS), Tsukuba, 305-0047 Japan
- Center for Emergent Matter Science (CEMS), RIKEN, Wako, 351-0198 Japan
- PRESTO, Japan Science and Technology Agency (JST), Saitama, Japan
| | - H. Nakao
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, 305-0801 Japan
| | - Y. Murakami
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, 305-0801 Japan
| | - T. Ogura
- Department of Physics and Mathematics, Aoyama-Gakuin University, Sagamihara, Kanagawa 252-5258 Japan
| | - Y. Kousaka
- Department of Physics and Electronics, Osaka Prefecture University, Osaka, 599-8531 Japan
| | - J. Akimitsu
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, 700-8530 Japan
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4
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Togawa Y, Kishine J, Nosov PA, Koyama T, Paterson GW, McVitie S, Kousaka Y, Akimitsu J, Ogata M, Ovchinnikov AS. Anomalous Temperature Behavior of the Chiral Spin Helix in CrNb_{3}S_{6} Thin Lamellae. Phys Rev Lett 2019; 122:017204. [PMID: 31012683 DOI: 10.1103/physrevlett.122.017204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 10/19/2018] [Indexed: 06/09/2023]
Abstract
Using Lorentz transmission electron microscopy and small-angle electron scattering techniques, we investigate the temperature-dependent evolution of a magnetic stripe pattern period in thin-film lamellae of the prototype monoaxial chiral helimagnet CrNb_{3}S_{6}. The sinusoidal stripe pattern appears due to formation of a chiral helimagnetic order (CHM) in this material. We found that as the temperature increases, the CHM period is initially independent of temperature and then starts to shrink above the temperature of about 90 K, which is far below the magnetic phase transition temperature for the bulk material T_{c} (123 K). The stripe order disappears at around 140 K, far above T_{c}. We argue that this cascade of transitions reflects a three-stage hierarchical behavior of melting in two dimensions.
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Affiliation(s)
- Y Togawa
- Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan
- School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ United Kingdom
| | - J Kishine
- Division of Natural and Environmental Sciences, The Open University of Japan, Chiba 261-8586, Japan
| | - P A Nosov
- Department of Physics, St. Petersburg State University, St. Petersburg 198504, Russia
- NRC Kurchatov Institute, Petersburg Nuclear Physics Institute, Gatchina 188300, Russia
| | - T Koyama
- Department of Materials Science, Osaka Prefecture University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan
| | - G W Paterson
- School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ United Kingdom
| | - S McVitie
- School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ United Kingdom
| | - Y Kousaka
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - J Akimitsu
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - M Ogata
- Department of Physics, the University of Tokyo, Hongo, Bunkyo, Tokyo 113-0033, Japan
| | - A S Ovchinnikov
- Institute of Natural Sciences and Mathematics, Ural Federal University, Ekaterinburg 620083, Russia
- Institute for Metal Physics, Ural Division of RAS, Ekaterinburg 620137, Russia
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5
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Kousaka Y, Ogura T, Zhang J, Miao P, Lee S, Torii S, Kamiyama T, Campo J, Inoue K, Akimitsu J. Long Periodic Helimagnetic Ordering in CrM3S6(M = Nb and Ta). ACTA ACUST UNITED AC 2016. [DOI: 10.1088/1742-6596/746/1/012061] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Leonov AO, Togawa Y, Monchesky TL, Bogdanov AN, Kishine J, Kousaka Y, Miyagawa M, Koyama T, Akimitsu J, Koyama T, Harada K, Mori S, McGrouther D, Lamb R, Krajnak M, McVitie S, Stamps RL, Inoue K. Chiral Surface Twists and Skyrmion Stability in Nanolayers of Cubic Helimagnets. Phys Rev Lett 2016; 117:087202. [PMID: 27588877 DOI: 10.1103/physrevlett.117.087202] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Indexed: 06/06/2023]
Abstract
Theoretical analysis and Lorentz transmission electron microscopy (LTEM) investigations in an FeGe wedge demonstrate that chiral twists arising near the surfaces of noncentrosymmetric ferromagnets [Meynell et al., Phys. Rev. B 90, 014406 (2014)] provide a stabilization mechanism for magnetic Skyrmion lattices and helicoids in cubic helimagnet nanolayers. The magnetic phase diagram obtained for freestanding cubic helimagnet nanolayers shows that magnetization processes differ fundamentally from those in bulk cubic helimagnets and are characterized by the first-order transitions between modulated phases. LTEM investigations exhibit a series of hysteretic transformation processes among the modulated phases, which results in the formation of the multidomain patterns.
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Affiliation(s)
- A O Leonov
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- IFW Dresden, Postfach 270016, D-01171 Dresden, Germany
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
| | - Y Togawa
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Osaka Prefecture University, 1-2 Gakuencho, Sakai, Osaka 599-8570, Japan
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
- JST, PRESTO, 4-1-8 Honcho Kawaguchi, Saitama 333-0012, Japan
| | - T L Monchesky
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 3J5, Canada
| | - A N Bogdanov
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- IFW Dresden, Postfach 270016, D-01171 Dresden, Germany
| | - J Kishine
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- The Open University of Japan, Chiba 261-8586, Japan
| | - Y Kousaka
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - M Miyagawa
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - T Koyama
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - J Akimitsu
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Ts Koyama
- Osaka Prefecture University, 1-2 Gakuencho, Sakai, Osaka 599-8570, Japan
| | - K Harada
- Osaka Prefecture University, 1-2 Gakuencho, Sakai, Osaka 599-8570, Japan
| | - S Mori
- Osaka Prefecture University, 1-2 Gakuencho, Sakai, Osaka 599-8570, Japan
| | - D McGrouther
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - R Lamb
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - M Krajnak
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - S McVitie
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - R L Stamps
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - K Inoue
- Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- IAMR, Facility of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
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7
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Togawa Y, Kousaka Y, Nishihara S, Inoue K, Akimitsu J, Ovchinnikov AS, Kishine J. Interlayer magnetoresistance due to chiral soliton lattice formation in hexagonal chiral magnet CrNb3S6. Phys Rev Lett 2013; 111:197204. [PMID: 24266487 DOI: 10.1103/physrevlett.111.197204] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 10/02/2013] [Indexed: 06/02/2023]
Abstract
We investigate the interlayer magnetoresistance (MR) along the chiral crystallographic axis in the hexagonal chiral magnet CrNb3S6. In a region below the incommensurate-commensurate phase transition between the chiral soliton lattice and the forced ferromagnetic state, a negative MR is obtained in a wide range of temperature, while a small positive MR is found very close to the Curie temperature. Normalized data of the negative MR almost falls into a single curve and is well fitted by a theoretical equation of the soliton density, meaning that the origin of the MR is ascribed to the magnetic scattering of conduction electrons by a nonlinear, periodic, and countable array of magnetic soliton kinks.
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Affiliation(s)
- Y Togawa
- N2RC, Osaka Prefecture University, 1-2 Gakuencho, Sakai, Osaka 599-8570, Japan and JST, PRESTO, 4-1-8 Honcho Kawaguchi, Saitama 333-0012, Japan
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8
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Tomiyasu K, Yokobori T, Kousaka Y, Bewley RI, Guidi T, Watanabe T, Akimitsu J, Yamada K. Emergence of highly degenerate excited states in the frustrated magnet MgCr2O4. Phys Rev Lett 2013; 110:077205. [PMID: 25166402 DOI: 10.1103/physrevlett.110.077205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Indexed: 06/03/2023]
Abstract
High degeneracy in ground states leads to the generation of exotic zero-energy modes, a representative example of which is the formation of molecular spin-liquid-like fluctuations in a frustrated magnet. Here we present single-crystal inelastic neutron scattering results for the frustrated magnet MgCr(2)O(4), which show that a common set of finite-energy molecular spin excitation modes is sustained in both the liquid-like phase above magnetic ordering temperature T(N) and an ordered phase with an extremely complex magnetic structure below T(N). Based on this finding, we propose the concept of high degeneracy in excited states, which promotes local resonant elementary excitations. This concept is expected to have ramifications on our understanding of excitations in many complex systems, including not only spin but also atomic liquids, complex order systems, and amorphous systems.
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Affiliation(s)
- K Tomiyasu
- Department of Physics, Tohoku University, Aoba, Sendai 980-8578, Japan
| | - T Yokobori
- Department of Physics and Mathematics, Aoyama-Gakuin University, Sagamihara 229-8558, Japan
| | - Y Kousaka
- Department of Physics and Mathematics, Aoyama-Gakuin University, Sagamihara 229-8558, Japan
| | - R I Bewley
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - T Guidi
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - T Watanabe
- Department of Physics, College of Science and Technology (CST), Nihon University, Chiyoda, Tokyo 101-8308, Japan
| | - J Akimitsu
- Department of Physics and Mathematics, Aoyama-Gakuin University, Sagamihara 229-8558, Japan
| | - K Yamada
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Oho, Tsukuba 305-0801, Japan
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Togawa Y, Koyama T, Takayanagi K, Mori S, Kousaka Y, Akimitsu J, Nishihara S, Inoue K, Ovchinnikov AS, Kishine J. Chiral magnetic soliton lattice on a chiral helimagnet. Phys Rev Lett 2012; 108:107202. [PMID: 22463448 DOI: 10.1103/physrevlett.108.107202] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Indexed: 05/17/2023]
Abstract
Using Lorenz microscopy and small-angle electron diffraction, we directly present that the chiral magnetic soliton lattice (CSL) continuously evolves from a chiral helimagnetic structure in small magnetic fields in Cr(1/3)NbS2. An incommensurate CSL undergoes a phase transition to a commensurate ferromagnetic state at the critical field strength. The period of a CSL, which exerts an effective potential for itinerant spins, is tuned by simply changing the field strength. Chiral magnetic orders observed do not exhibit any structural dislocation, indicating their high stability and robustness in Cr(1/3)NbS2.
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Affiliation(s)
- Y Togawa
- N2RC, Osaka Prefecture University, 1-2 Gakuencho, Sakai, Osaka 599-8570, Japan
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10
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Nishikawa Y, Kousaka Y, Tragoolpua K, Xuan X, Makala L, Fujisaki K, Mikami T, Nagasawa H. Characterization of Neospora caninum surface protein NcSRS2 based on baculovirus expression system and its application for serodiagnosis of Neospora infection. J Clin Microbiol 2001; 39:3987-91. [PMID: 11682519 PMCID: PMC88476 DOI: 10.1128/jcm.39.11.3987-3991.2001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The baculovirus expression system has proved to be a useful tool for the production of recombinant proteins. Here we have characterized the Neospora caninum surface protein NcSRS2 produced by two types of the recombinant virus and also have developed an enzyme-linked immunosorbent assay (ELISA) using recombinant NcSRS2 for the serologic diagnosis of Neospora infection. Western blot analysis showed two major protein bands that were detectable in insect cells infected with each recombinant baculovirus, and a lower-molecular-weight protein was detected in culture supernatants from a cell infected with the recombinant virus lacking the hydrophobic C-terminal tail. Analysis of the N-terminal amino acids showed that the secreted NcSRS2 lacked 6 kDa of the N-terminal signal peptide. Moreover, the detergent-soluble protein of insect cells infected with the recombinant baculovirus expressing the full-length NcSRS2 gene was used to develop an ELISA system based on specificity and reactivity to antisera against Toxoplasma gondii, Hammondia heydorni, or N. caninum. Anti-N. caninum mouse, dog, and bovine sera recognized the recombinant NcSRS2 on Western blots. Furthermore, we have shown that the developed ELISA system consistently discriminates indirect fluorescent-antibody test (IFAT)-positive bovine sera against N. caninum from IFAT-negative sera. These results indicate that the ELISA using baculovirus-expressed NcSRS2 can be useful for effective and reliable serodiagnosis of N. caninum infection.
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Affiliation(s)
- Y Nishikawa
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
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11
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Nomura T, Alonso M, Kousaka Y, Tenjiku E. Simple Model of Aerosol Particle Formation by the Evaporation-Condensation Method. J Colloid Interface Sci 2000; 231:107-113. [PMID: 11082254 DOI: 10.1006/jcis.2000.7127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
From an engineering point of view the present authors have proposed the simple model of a homogeneous nucleation relationship in the liquid phase that can predict the number concentration of nucleated particles in various operating conditions. Experiments of liquid-phase nucleation in which the precursor monomers were generated by several methods have successfully confirmed the predictions of the model. In the present paper, our previous model of homogeneous nucleation is extended to the case in which the precursor monomers are generated in a gas-phase system. First, a relationship between number concentration and mean volume diameter of nucleated aerosol particles and operating conditions is obtained considering the free molecular regime around the critical nuclei, which is the main difference with the liquid phase. Second, the validity of the relation lies in experimental use of dioctyl sebacate particles generated by evaporation-condensation. As a result, the predictions are in excellent agreement with the experimental results after considering substantial losses of monomers and particles to the walls of the experimental system because in the gasphase the diffusion velocity and the critical supersaturation ratio of monomer are higher than those in the liquid phase. Copyright 2000 Academic Press.
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Affiliation(s)
- T Nomura
- Chemical Engineering Department, Osaka Prefecture University, 1-1 Gakuencho, Sakai, 599-8531, Japan
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12
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Nishikawa Y, Kousaka Y, Fukumoto S, Xuan X, Nagasawa H, Igarashi I, Fujisaki K, Otsuka H, Mikami T. Delivery of Neospora caninum surface protein, NcSRS2 (Nc-p43), to mouse using recombinant vaccinia virus. Parasitol Res 2000; 86:934-9. [PMID: 11097303 DOI: 10.1007/s004360000267] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In order to develop a vaccine against Neospora caninum in dogs and cattle, we constructed a recombinant vaccinia virus expressing the N. caninum surface protein, NcSRS2 (Nc-p43). Monoclonal antibodies to NcSRS2 and anti-N. caninum tachyzoite mouse serum recognized the NcSRS2 expressed by the recombinant vaccinia virus. In addition, recombinant NcSRS2 was transported to the cell surface. Mice infected with the recombinant virus predominantly produced IgG1 antibody (Ab) to N. caninum, rather than producing IgG2a Ab. Moreover, splenocytes from mice infected with the recombinant virus proliferated in the presence of the N. caninum antigen. Mice immunized with the recombinant virus gave rise to humoral and cellular immune responses to N. caninum tachyzoites. This study showed that a recombinant vaccinia virus expressing NcSRS2 might be useful for the production of a live vaccine against N. caninum infection.
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Affiliation(s)
- Y Nishikawa
- The National Research Center for Protozoan Diseases, Obihiro University, Hokkaido, Japan
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Abstract
Zinc sulfide particles were homogeneously precipitated by thermal decomposition of thioacetamide in acidic aqueous solutions in a one-step process. The influence of the operating conditions (initial concentration of zinc ion and TAA) on the nucleation time and number concentration of the generated particles was investigated. The experimental results show that the model of homogeneous nucleation previously developed and successfully tested for silver particle generation by a chemical reduction method can also be applied to the formation of zinc sulfide particles by homogeneous precipitation. Furthermore, in the particle formation method in which the nucleation time t* can be measured, the particle number concentration n* can be predicted by the simple relation n*=1/(4pir*Dt*) (r* is the critical nucleus radius, and D the monomer diffusion coefficient). Thus the particle number concentration can be easily predicted even if the rate expression and the critical supersaturation concentration are unknown. Copyright 2000 Academic Press.
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Affiliation(s)
- T Nomura
- Chemical Engineering Department, Osaka Prefecture University, 1-1 Gakuencho, Sakai, 599-8531, Japan
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Nomura T, Kousaka Y, Alonso M, Fukunaga M, Satoh T. A Model for Simultaneous Homogeneous and Heterogeneous Nucleation in the Case of Slow Reaction Rate. J Colloid Interface Sci 2000; 221:195-199. [PMID: 10631020 DOI: 10.1006/jcis.1999.6588] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Our previous model for simultaneous homogeneous and heterogeneous nucleation, which was successfully tested for silver particle generation by a chemical reduction method, is extended to the case of slow reaction rate. Nucleation in a system containing seed particles in the case where the reaction rate is slow occurs according to the following rule: homogeneous nucleation is predominant when n(p)/n(0)(*),>1 (n(p) is the seed number concentration, and n(0)(*) the number concentration of homogeneously nucleated particles without seed particles), and heterogeneous nucleation is predominant when n(p)/n(0)(*)<1. This theoretical prediction is in good agreement with the experimental results obtained for zinc sulfide particles generated by homogeneous precipitation. Copyright 2000 Academic Press.
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Affiliation(s)
- T Nomura
- Chemical Engineering Department, Osaka Prefecture University, 1-1 Gakuencho, Sakai, 599-8531, Japan
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Takechi M, Kousaka Y, Uno C, Tanaka Y. Biological activities of synthetic triterpenoid and steroid beta-D-glucopyranosyl-(1-->2)-alpha-D-glucopyranosides. Planta Med 1998; 64:179-180. [PMID: 9525112 DOI: 10.1055/s-2006-957400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Comparisons of the biological activities of diosgenyl, methyl glycyrrhetinate, or digitoxigenyl 3-O-beta-D-glucopyranosyl-(1-->2)-alpha-D-glucopyranoside with those of other previously tested glycosides confirmed our assumption that both haemolytic and antifungal activities of steroid saponins are generally parallel to each other, while almost all haemolytic triterpenoid saponins have no antifungal activity. The earlier supposition that cardiac diglycosides having a (1-->4) sugar linkage have stronger activities than those with a (1-->6) linkage has been extended by the demonstration of reduced activity also in those with a (1-->2) linkage.
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Okuyama K, Kousaka Y, Yamamoto S, Hosokawa T. Particle loss of aerosols with particle diameters between 6 and 2000 nm in stirred tank. J Colloid Interface Sci 1986. [DOI: 10.1016/0021-9797(86)90370-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Okuyama K, Kousaka Y, Hayashi K. Change in size distribution of ultrafine aerosol particles undergoing Brownian coagulation. J Colloid Interface Sci 1984. [DOI: 10.1016/0021-9797(84)90011-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Okuyama K, Kousaka Y, Payatakes A. Evaluation of the effect of nonsphericity of fine aggregate particles in brownian coagulation. J Colloid Interface Sci 1981. [DOI: 10.1016/0021-9797(81)90297-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Liu B, Pui D, Whitby K, Kittelson D, Kousaka Y, McKenzie R. The aerosol mobility chromatograph: A new detector for sulfuric acid aerosols. ACTA ACUST UNITED AC 1978. [DOI: 10.1016/0004-6981(78)90192-0] [Citation(s) in RCA: 119] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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