2007 Fiscal Year Final Research Report Summary
Gigantic magnetoelectric effect in ferroelectric-magnets
| Project/Area Number |
17340104
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | The University of Tokyo |
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Principal Investigator |
TOKURA Yoshinori The University of Tokyo, Graduated School of Engineering, professor (30143382)
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| Co-Investigator(Kenkyū-buntansha) |
ONOSE Yoshinori The University of Tokyo, Graduated School of Engineering, Lecturer (80436526)
IGUCHI Satoshi The University of Tokyo, Graduated School of Engineering, Research Associate (50431789)
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| Project Period (FY) |
2005 – 2007
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| Keywords | Magnetoelectric effect / Ferroelectrics / Ferromagnets / Cross-correlation / Strongly-correlated electronics / Magnetic ferroelectrics |
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| Research Abstract |
In this study we have developed the magnetic ferroelectric oxides which may host the gigantic magnetoelectric effect. We could control the electric polarization in the materials by magnetic field as the gigantic magnetoelectric effect, and some times the magnetic structure itself by electric field as the reciprocal effect. The gigantic optical magnetoelectric (magneto-chiral) effect was also observed.
We have aimed at the realization of the gigantic magnetoelectric effect, and found new magnetic ferroelectrics based on the time and space symmetry breaking, multicriticality of electronic phases, and the chirality in lattices and frustration of spins. We have found magnetic ferroelectricity in perovskite type manganites RMnO_3 and Pr(Sr, Ca)_2Mn_2O_7, spinets CoCr_2O_4, and low dimensional frustration oxides Cu(Fe, Al)O_2, and LiCu_2O_2, in which polarization was controlled by magnetic field. Furthermore the change of the magnetic chirality with external electric field was confirmed by synchrotron x ray radiation, and neutron scattering studies.
The gigantic optical magnetoelectric effect has various potentials for the new optical devices such as an optical isolator in the optical communication. We have succeeded in the synthesis of the single crystals of the rare earth metal doped (Ba, Sr)TiO_3, La_2Ti_2O_7 and so on, and observed the emission spectra due to the optical magnetoelectric effect. Moreover, we observed the optical magnetoelectric response stem from the magnetic interface of the tailor-made tricolor superlattice of LaMnO_3/SrMnO_3/LaAlO_3.
In collaboration with theory groups, we show the origins of these effects are the unconventional magnetoelectric coupling characterized by the quantities of spin current and toroidal moment. We believe that this made a great contribution to the progress of the new spintronics.
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Research Products
(100 results)
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[Presentation] Toward Electrical Control of Magnetism2007
Author(s)
Y. Tokura
Organizer
The 21st COE International Symposium on the Linear Response Theory in Commemoration of its 50th Anniversary-Recent Development in Equilibrium and Non-Equilibrium Response-
Place of Presentation
Koshiba Hall, University of Tokyo, Japan
Year and Date
2007-11-06
Description
「研究成果報告書概要(和文)」より
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[Presentation] Toward Electrical Control of Magnetism2007
Author(s)
Y. Tokura
Organizer
The 21st COE International Symposium on the Linear Response Theory in Commemoration of its 50th Anniversary- Recent Development in Equilibrium and Non-Equilibrium Response
Place of Presentation
Koshiba Hall, University of Tokyo, Japan
Year and Date
2007-11-06
Description
「研究成果報告書概要(欧文)」より
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[Presentation] Mutual Control of Magnetism and Electricity in Multiferroics2007
Author(s)
Y. Tokura
Organizer
The 6th Asia-Pacific Workshop on Frontiers of Condensed-Matter Science and Symposium on 20-years Anniversary of Discovery of YBCO
Place of Presentation
International Conference Hall Building for Humanities and Social Sciences Academia Sinica, Taipei
Year and Date
2007-04-16
Description
「研究成果報告書概要(和文)」より
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