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August 9
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Aug. 9 - 3a
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10:30 - 11:00
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11:00 - 11:30
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11:30 - 12:00
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| Dynamics and magnetization process of triangle based low dimensional systems, ring, tube, helix and ball |
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Hiroyuki Nojiri |
| A spin chirality brings a new internal degree of freedom in spin systems made up of triangular spin rings such as prism, tube, helix and polyhedron. The cross term of the chirality and the spin gives rise to a variety of magnetic properties in such systems. A simple but interesting example is found in the spin ring. A purely adiabatic magnetization process is confirmed by the observation of half-step magnetization. Similar behavior is found in a spin polyhedron of tri-diminished icosihedron, where the ground state is doubly degenerated. In spin polyhedron of huge number of states, the magnetization plateau is found at the 1/3 of saturation and is interpreted by the order by disorder mechanism.
It is also important that the spin chirality is closely connected with the structural chirality. In a triangle ring, the distortion from the regular triangle mostly results in the chiral structure that gives the difference between the upward and the downward directions in the spin ring. When such chiral rings are connected into a chain, a helix of mono-chirality can be formed and the non-linear properties are expected in both dielectric and magnetic sectors. |