2017 Fiscal Year Annual Research Report
Non-axisymmetric skyrmions in chiral and frustrated magnets
| Project/Area Number |
17H06889
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| Research Institution | Hiroshima University |
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Principal Investigator |
LEONOV ANDRIY 広島大学, 理学研究科, 助教 (30804851)
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| Project Period (FY) |
2017-08-25 – 2019-03-31
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| Keywords | skyrmion / chiral magnet |
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| Outline of Annual Research Achievements |
In collaboration with a group from Augsburg lead by Prof. Kezsmarki, I published 3 papers (2 Phys. Rev. B and Scientific Reports) on a new class of isolated magnetic skyrmions emerging within tilted ferromagnetic phases of polar magnets with easy-plane anisotropy. Thus the developed theory was fully supported by the experiments in lacunar spinels hosting Neel-type skyrmions.We also demonstrated that the stability range of skyrmions can be drastically increased in systems with restricted geometries, such as thin films, interfaces and nanowires. Thermal quenching can also promote the skyrmion lattice as a metastable state over extended temperature ranges.
In collaboration with the group from Department of Materials Science and Metallurgy,Cambridge, we also experimentally observed attractive skyrmions and skyrmion clusters in thin (70 nm) single-crystal samples of Cu2OSeO3 taken using transmission electron microscopy. We developed a phenomenological theory describing this type of skyrmion and published the results in Phys. Rev. B.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
5 papers have been published on chiral skyrmions including the first experimental elucidation of the attractive skyrmions in CuOSeO.
Due to the lots of different results on chiral skyrmions, the research on frustrated skyrmions has been temporarily put off till the next year.
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| Strategy for Future Research Activity |
The future plans include:
1. Description of the formation of isolated chiral skyrmions by homogeneous and heterogeneous nucleation in thin layers of cubic helimagnets via elongation of torons and chiral bobbers, correspondingly. Both torons and bobbers are localized in three dimensions, contain singularities, and according to the theoretical analysis within the standard phenomenological models can exist as metastable states in saturated and modulated phases of noncentrosymmetric ferromagnets.They represent new types of particle-like states in chiral magnets and liquid crystals.
2. Description of a new type of non-axisymmetric skyrmions arising within the conical phase with its axis perpendicular to the field. Such a skyrmion transforms into a pair of merons at lower fields.
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[Journal Article] Equilibrium Skyrmion Lattice Ground State in a Polar Easy-plane Magnet2017
Author(s)
S. Bordacs, A. Butykai, B. G. Szigeti, J. S. White, R. Cubitt, A. O. Leonov, S. Widmann, D. Ehlers, H.-A. Krug von Nidda, V. Tsurkan, A. Loidl & I. Kezsmarki
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Journal Title
Scientific Reports
Volume: 7
Pages: 7584
DOI
Peer Reviewed / Int'l Joint Research
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