Yoshinori Tokura

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Magnetic skyrmions are particle-like nanometre-sized spin textures of topological origin found in several magnetic materials, and are characterized by a long lifetime. Skyrmions have been observed both by means of neutron scattering in momentum space and microscopy techniques in real space, and their properties include novel Hall effects, current-driven(More)
Efforts to find the magnetic monopole in real space have been made in cosmic rays and in particle accelerators, but there has not yet been any firm evidence for its existence because of its very heavy mass, approximately 10(16) giga-electron volts. We show that the magnetic monopole can appear in the crystal momentum space of solids in the accessible(More)
M. Reehuis,1,2 C. Ulrich,1 P. Pattison,3,4 B. Ouladdiaf,5 M. C. Rheinstädter,5 M. Ohl,6 L. P. Regnault,7 M. Miyasaka,8 Y. Tokura,8,9 and B. Keimer1 1Max-Planck-Institut für Festkörperforschung, D-70569 Stuttgart, Germany 2Hahn-Meitner-Institut, D-14109 Berlin, Germany 3SNBL at ESRF, BP 220, F-38042 Grenoble Cedex 9, France 4Laboratory of Crystallography,(More)
The electrical manipulation of magnetism and magnetic properties has been achieved across a number of different material systems. For example, applying an electric field to a ferromagnetic material through an insulator alters its charge-carrier population. In the case of thin films of ferromagnetic semiconductors, this change in carrier density in turn(More)
Helical spin order in magnetic materials has been investigated only in reciprocal space. We visualized the helical spin order and dynamics in a metal silicide in real space by means of Lorentz electron microscopy. The real space of the helical spin order proves to be much richer than that expected from the averaged structure; it exhibits a variety of(More)
Ferroelectric polarization of 6.3  μC cm(-2) is induced by the neutral-to-ionic transition, upon which nonpolar molecules of electron donor tetrathiafulvalene (TTF) and acceptor p-chloranil (CA) are incompletely ionized to ±0.60e and dimerized along the molecular stacking chain. We find that the ferroelectric properties are governed by intermolecular charge(More)
A phase transition in an organic charge-transfer complex, which originates from the neutral-ionic valence instability, can be tuned toward zero kelvin with use of external pressure or chemical modification as a control parameter. The phase diagram and observed dielectric behaviors are typical of quantum paraelectricity, yet this zero-kelvin transition point(More)
1. S. Picozzi, C. Ederer, J. Phys. Condens. Matter 21, 303201 (2009). 2. T. Kimura, Annu. Rev. Condens. Matter Phys. 3, 93–110 (2012). 3. X. Rocquefelte, K. Schwarz, P. Blaha, S. Kumar, J. van den Brink, Nat. Commun. 4, 2511 (2013). 4. K. Noda, M. Akaki, T. Kikuchi, D. Akahoshi, H. Kuwahara, J. Appl. Phys. 99, 08S905 (2006). 5. N. Abe et al., Phys. Rev.(More)
Controlling ferromagnetism by an external electric field has been a great challenge in materials physics, for example towards the development of low-power-consumption spintronics devices. To achieve an efficient mutual control of electricity and magnetism, the use of multiferroics--materials that show both ferroelectric and ferromagnetic/antiferromagnetic(More)
Interface-selective probing of magnetism is a key issue for the design and realization of spin-electronic junction devices. Here, magnetization-induced second-harmonic generation was used to probe the local magnetic properties at the interface of the perovskite ferromagnet La(0.6)Sr(0.4)MnO3 with nonmagnetic insulating layers, as used in spin-tunnel(More)