Publication

Original Paper

  1. “Low-field bi-skyrmion formation in a noncentrosymmetric chimney ladder ferromagnet”
    R. Takagi, X. Z. Yu, J. S. White, K. Shibata, Y. Kaneko, G. Tatara, H. M. Ronnow, Y. Tokura, S. Seki
    Phys. Rev. Lett. 120, 037203 (2018).

  2. “Stabilization of magnetic skyrmions by uniaxial tensile strain”
    S. Seki, Y. Okamura, K. Shibata, R. Takagi, N. D. Khanh, F. Kagawa, T. Arima, Y. Tokura
    Phys. Rev. B 96, 220404(R) (2017).

  3. “Emergence and magnetic-field variation of chiral-soliton lattice and skyrmion lattice in the strained helimagnet Cu2OSeO3
    Y. Okamura, Y. Yamasaki, D. Morikawa, T. Honda, V. Ukleev, H. Nakao, Y. Murakami, K. Shibata, F. Kagawa, S. Seki, T. Arima, and Y. Tokura
    Phys. Rev. B 96, 174417 (2017).

  4. “Nonlinear Ultrafast Spin Scattering in the Skyrmion Phase of Cu2OSeO3
    M. C. Langner, S. Roy, S. W. Huang, J. D. Koralek, Y.-D. Chuang, G. L. Dakovski, J. J. Turner, J. S. Robinson, R. N. Coffee, M. P. Minitti, S. Seki, Y. Tokura, R. W. Schoenlein
    Phys. Rev. Lett. 119, 107204 (2017).

  5. “Spin-wave spectroscopy of the Dzyaloshinskii-Moriya interaction in room-temperature chiral magnets hosting skyrmions”
    R. Takagi, D. Morikawa, K. Karube, N. Kanazawa, K. Shibata, G. Tatara, Y. Tokunaga, T. Arima, Y. Taguchi, Y. Tokura, S. Seki
    Phys. Rev. B 95, 220406(R) (2017). (arXiv:1705.09001)

  6. “Directional electric-field induced transformation from skyrmion lattice to distinct helices in multiferroic Cu2OSeO3
    Y. Okamura, Y. Yamasaki, D. Morikawa, T. Honda, V. Ukleev, H. Nakao, Y. Murakami, K. Shibata, F. Kagawa, S. Seki, T. Arima, Y. Tokura.
    Phys. Rev. B 95, 184411 (2017).

  7. “Thermal stability and irreversibility of skyrmion-lattice phases in Cu2OSeO3
    K. Makino, J. D. Reim, D. Higashi, D. Okuyama, T. J. Sato, Y. Nambu, E. P. Gilbert, N. Booth, S. Seki, Y. Tokura
    Phys. Rev. B 95, 134412 (2017). (arXiv:1608.06359)

  8. “Transition to and from the skyrmion lattice phase by electric fields in a magnetoelectric compound”
    Y. Okamura, F. Kagawa, S. Seki, and Y. Tokura
    Nature Communications 7, 12669 (2016).

  9. “Magnetic reversal of electric polarization with fixed chirality of magnetic structure in a chiral-lattice helimagnet MnSb2O6
    M. Kinoshita, S. Seki, T. J. Sato, Y. Nambu, T. Hong, M. Matsuda, H. Cao, S. Ishiwata, and Y. Tokura
    Phys. Rev. Lett. 117, 047201 (2016).

  10. “Magnetochiral nonreciprocity of volume spin wave propagation in chiral-lattice ferromagnets”
    S. Seki, Y. Okamura, K. Kondou, K. Shibata, M. Kubota, R. Takagi, F. Kagawa, M. Kawasaki, G. Tatara, Y. Otani, and Y. Tokura
    Phys. Rev. B 93, 235131 (2016). (arXiv:1505.02868)

  11. “Thermal generation of spin current in a multiferroic helimagnet”
    R. Takagi, Y. Tokunaga, T. Ideue, Y. Taguchi, Y. Tokura and S. Seki
    APL Mater. 4, 032502 (2016). [invited] (arXiv:1602.04011)

  12. “Thermal generation of spin current in an antiferromagnet”
    S. Seki, T. Ideue, M. Kubota, Y. Kozuka, R. Takagi, M. Nakamura, Y. Kaneko, M. Kawasaki, and Y. Tokura
    Phys. Rev. Lett. 115, 266601 (2015). [Editor's Suggestion, Highlighted in Nature Nanotechnology and Physics] (arXiv:1508.02555)

  13. “Microwave Magnetochiral Dichroism in the Chiral-Lattice Magnet Cu2OSeO3
    Y. Okamura, F. Kagawa, S. Seki, M. Kubota, M. Kawasaki, and Y. Tokura
    Phys. Rev. Lett. 114, 197202 (2015).

  14. “Ultrafast optical excitation of magnetic skyrmions”
    N. Ogawa, S. Seki and Y. Tokura
    Scientific Reports 5, 9552 (2015).

  15. “Magnetochiral dichroism resonant with electromagnons in a helimagnet”
    S. Kibayashi, Y. Takahashi, S. Seki, and Y. Tokura
    Nature Communications 5, 4583 (2014).

  16. “Coupled skyrmion sublattices in Cu2OSeO3
    M.C. Langner, S. Roy, S. K. Mishra, J. C. T. Lee, X. W. Shi, M. A. Hossain, Y.-D. Chuang, S. Seki, Y. Tokura, S. D. Kevan, and R. W. Schoenlein
    Phys. Rev. Lett. 112, 167202 (2014). (arXiv:1402.2947)

  17. “Thermally driven ratchet motion of a skyrmion microcrystal and topological magnon Hall effect”
    M. Mochizuki, X. Z. Yu, S. Seki, N. Kanazawa, W. Koshibae, J. Zang, M. Mostovoy, Y. Tokura, and N. Nagaosa
    Nature Materials 13, 241 (2014).

  18. “Microwave magnetoelectric effect via skyrmion resonant modes in a helimagnetic multiferroics”
    Y. Okamura, F. Kagawa, M. Mochizuki, M. Kubota, S. Seki, S. Ishiwata, M. Kawasaki, Y. Onose, and Y. Tokura
    Nature Communications 4, 2391 (2013).

  19. “Optimal Tc for electron-doped cuprate realized under high pressure”
    S. Ishiwata, D. Kotajima, N. Takeshita, C. Terakura, S. Seki, and Y. Tokura
    J. Phys. Soc. Jpn. 82, 063705 (2013).

  20. “Superconductivity in CuxIrTe2 driven by interlayer hybridization”
    M. Kamitani, M. S. Bahramy, R. Arita, S. Seki, T. Arima, Y. Tokura, and S. Ishiwata
    Phys. Rev. B 87, 180501 (2013).

  21. “Magnetoelectric resonances and predicted microwave diode effect of the skyrmion crystal in a multiferroic chiral-lattice magnet”
    M. Mochizuki and S. Seki
    Phys. Rev. B 87, 134403 (2013). (arXiv:1303.4491v1)

  22. “Magnetoelectric responses induced by domain rearrangement and spin structural change in triangular-lattice helimagnets NiI2 and CoI2
    T. Kurumaji, S. Seki, S. Ishiwata, H. Murakawa, Y. Kaneko, and Y. Tokura
    Phys. Rev. B 87, 014429 (2013).

  23. “Magnetoelectric nature of skyrmions in a chiral magnetic insulator Cu2OSeO3
    S. Seki, S. Ishiwata, and Y. Tokura
    Phys. Rev. B 86, 060403(R) (2012). (arXiv:1206.4404v1)

  24. “Observation of magnetic excitations of skyrmion crystal in a helimagnetic insulator Cu2OSeO3
    Y. Onose, Y. Okamura, S. Seki, S. Ishiwata, and Y. Tokura
    Phys. Rev. Lett. 109, 037603 (2012). (arXiv:1204.5009v1)

  25. “Formation and rotation of skyrmion crystal in the chiral-lattice insulator Cu2OSeO3
    S. Seki, J.-H. Kim, D. S. Inosov, R. Georgii, B. Keimer, S. Ishiwata, and Y. Tokura
    Phys. Rev. B 85, 220406(R) (2012). (arXiv:1206.5220v1)

  26. “Observation of Skyrmions in a Multiferroic Material”
    S. Seki, X. Z. Yu, S. Ishiwata, and Y. Tokura
    Science 336, 198 (2012).

  27. “Magnetic-field induced competition of two multiferroic orders in a triangular-lattice helimagnet MnI2
    T. Kurumaji, S. Seki, S. Ishiwata, H. Murakawa, Y. Tokunaga, Y. Kaneko, and Y. Tokura
    Phys. Rev. Lett. 106, 167206 (2011). (arXiv:1103.5294v1)

  28. “Effect of Spin Dilution on the Magnetic State of Delafossite CuCrO2 with an S = 3/2 Antiferromagnetic Triangular Sublattice”
    T. Okuda, K. Uto, S. Seki, Y. Onose, Y. Tokura, R. Kajimoto, and M. Matsuda
    J. Phys. Soc. Jpn. 80, 014711 (2011).

  29. “Electromagnons in the spin collinear state of a triangular lattice antiferromagnet”
    S. Seki, N. Kida, S. Kumakura, R. Shimano, and Y. Tokura
    Phys. Rev. Lett. 105, 097207 (2010). (arXiv:1008.4709v1)

  30. “Cupric chloride CuCl2 as an S = 1/2 chain multiferroic”
    S. Seki, T. Kurumaji, S. Ishiwata, H. Matsui, H. Murakawa, Y. Tokunaga, Y. Kaneko, T. Hasegawa, and Y. Tokura
    Phys. Rev. B 82, 064424 (2010). (arXiv:1008.5226v1)

  31. “Electronic structure, magnetic, and dielectric properties of the edge-sharing copper oxide chain compound NaCu2O2
    Ph. Leininger, M. Rahlenbeck, M. Raichle, B. Bohnenbuck, A. Maljuk, C. T. Lin, B. Keimer, E. Weschke, E. Schierle, S. Seki, Y. Tokura, and J. W. Freeland
    Phys. Rev. B 81, 085111 (2010). (arXiv:0912.0168v1)

  32. “Magnetic digital flop of ferroelectric domain with fixed spin chirality in a triangular lattice helimagnet”
    S. Seki, H. Murakawa, Y.Onose, and Y. Tokura
    Phys. Rev. Lett. 103, 237601 (2009). (arXiv:0906.0324v2)

  33. Effect of Quenched Disorder on Charge Ordering Structure in RE1.67AE0.33NiO4 (RE = La, Pr, Nd, Sm; AE = Ca, Sr)
    X. Yu, T. Arima, S. Seki, T. Asaka, K. Kimoto, Y. Tokura, and Y. Matsui
    J. Phys. Soc. Jpn. 77, 093709 (2008).

  34. “Spin-driven ferroelectricity in triangular lattice antiferromagnets ACrO2 (A = Cu, Ag, Li, or Na) “
    S. Seki, Y.Onose, and Y. Tokura
    Phys. Rev. Lett. 101, 067204 (2008). (arXiv:0801.3757v1)

  35. “Correlation between spin helicity and electric polarization vector in quantum-spin chain magnet LiCu2O2
    S. Seki, Y. Yamasaki, M. Soda, M. Matsuura, K. Hirota, Y. Tokura
    Phys. Rev. Lett. 100, 127201 (2008). (arXiv:0801.2533v1)

  36. “Impurity-doping-induced ferroelectricity in the frustrated antiferromagnet CuFeO2
    S. Seki, Y. Yamasaki, Y. Shiomi, S.Iguchi, Y.Onose, and Y. Tokura
    Phys. Rev. B 75, 100403(R) (2007). (arXiv:cond-mat/0611255v1)

Review Article

  1. “Noncentrosymmetric magnets hosting magnetic skyrmions”
    N. Kanazawa, S. Seki, Y. Tokura
    Adv. Mater. 29, 1603227 (2017).

  2. “Dynamical magnetoelectric phenomena of multiferroic skyrmions”
    M. Mochizuki, S. Seki
    J. Phys.: Condens. Matter 27, 503001 (2015). (arXiv:1511.07761)

  3. “Multiferroics of spin origin”
    Y. Tokura, S. Seki, N. Nagaosa
    Rep. Prog. Phys. 77, 076501 (2014).

  4. “Multiferroics with spiral spin orders”
    Y. Tokura, S. Seki
    Adv. Mater. 22, 1554 (2010).


Book

  1. “Skyrmions in Magnetic Materials”
    S. Seki, M. Mochizuki
    (2015, Springer, ISBN 978-3-319-24649-9)
  2. “Magnetoelectric Response in Low-Dimensional Frustrated Spin Systems”
    S. Seki
    (2012, Springer, ISBN 978-4-431-54090-8)


Invited Talk

  1. “Magnetoelectric Dynamics of Skyrmions”
    (Skyrmionics: Materials, Phenomena and Applications, Santa Fe (USA), 7/Aug/2017)
    S. Seki

  2. “Thermal generation of spin current in antiferromagnets and helimagnets”
    (Annual Conference on Magnetism and Magnetic Materials (MMM), New Orleans (USA), 1/Nov/2016)
    S. Seki

  3. “Emergent phenomena in chiral-lattice ferromagnetic insulators”
    (Asia Pacific Center for Theoretical Physics (APCTP) Workshop on Multiferroics, Shanghai (China), 9/Oct/2016)
    S. Seki

  4. “Control of skyrmions by electric field and mechanical strain”
    (International Workshop on Topological Structures in Ferroic Materials, Dresden (Germany), 19/Aug/2016)
    S. Seki

  5. “Chirality and Ferromagnetism”
    (Gordon Research Conference on Multiferroic and Magnetoelectric Materials, Lewiston (USA), 10/Aug/2016)
    S. Seki

  6. “Spin current in antiferromagnets and multiferroics”
    (Spin Caloritronics 7, Utrecht (Netherland), 15/Jul/2016)
    S. Seki

  7. “Spin dynamics in chiral multiferroic insulators with magnetic skyrmions”
    (International Workshop on Topological Structures in Ferroic Materials, Sydney (Australia), 20/May/2015)
    S. Seki

  8. “Magnetoelectric Skyrmions in Multiferroics”
    (INTERMAG, Beijing (China), 15/May/2015)
    S. Seki

  9. “Observation and Manipulation of Magnetic Skyrmions”
    (Annual Meeting of German Physical Society (DPG), Berlin (Germany), 18/Mar/2015)
    S. Seki

  10. “Skyrmions in Multiferroic Insulator”
    (Congress and general assembly of International Union of Crystallography (IUCr), Montreal (Canada), 12/Aug/2014)
    S. Seki

  11. “Observation and Manipulation of Multiferroic Skyrmions”
    (SKYMAG, Paris (France), 11/Apr/2014)
    S. Seki

  12. “Skyrmions in multiferroic insulator Cu2OSeO3
    (Super-PIRE REIMEI Workshop on Frontiers of Condensed Matter Physics, Beijing (China), 18/Mar/2014)
    S. Seki

  13. “Observation and manipulation of skyrmions in multiferroics”
    (Annual Magnetism and Magnetic Materials (MMM) Conference, Denver (USA), 8/Nov/2013)
    S. Seki

  14. “Multiferroic Skyrmions”
    (APCTP Workshop on Multiferroics, Singapore, 23/May/2013)
    S. Seki

  15. “Observation of Skyrmions in a Multiferroic Material”
    (American Physical Society (APS) March Meeting, Baltimore (USA), 18/Mar/2013)
    S. Seki

  16. “Magnetoelectric skyrmion in a Multiferroic Material”
    (International Symposium on Integrated Functionalities (ISIF), Hong Kong (China), 20/Jun/2012)
    S. Seki

Talk

  1. “Skyrmions in Multiferroics”
    (2012 American Physical Society March Meeting, Boston, (Q32.00001))
    S. Seki, X. Z. Yu, S. Ishiwata, and Y. Tokura

  2. “Transition-metal dihalide MX2 as magnetoelectric multiferroics”
    (2011 American Physical Society March Meeting, Dallas, (V22.00002))
    S. Seki, T. Kurumaji, S. Ishiwata, H. Matsui, H. Murakawa, Y. Tokunaga, Y. Kaneko, T. Hasegawa, and Y. Tokura

  3. “Spin-driven ferroelectricity in triangular lattice antiferromagnets ACrO2 (A = Cu, Ag, Li, or Na)”
    (2009 American Physical Society March Meeting, Pittsburgh, (L30.00008))
    S. Seki, Y. Onose, and Y. Tokura

  4. “Correlation between spin helicity and electric polarization vector in quantum chain magnet LiCu2O2
    (2008 American Physical Society March Meeting, New Orleans, (X23.00004))
    S. Seki, Y. Yamasaki, M. Soda, M. Matsuura, K. Hirota, and Y. Tokura

    (For other talks in Japan, please see a Japanese version of the page.)

Thesis

  • “Magnetoelectric response in low-dimensional frustrated spin systems”
    Ph.D Thesis (Sep. 2010, Duke’s award)

Award

  1. The Young Scientists’ Prize (The Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology)
    (Apr. 2014 Ministry of Education, Culture, Sports, Science and Technology)
    “Electric control of Magnetism”
  2. Young Scientist Award of the Physical Society of Japan
    (Mar. 2014 The Physical Society of Japan)
    “Observation of Magnetic Skyrmions in a Multiferroic Material”
  3. Inoue Research Award for Young Scientists
    (Feb. 2012, Inoue Foundation for Science)
    “Magnetoelectric response in low-dimensional frustrated spin systems”