| 研究実績の概要 |
Symmetry attracted persons in the broad field such as mathematics, physics, chemistry, material science, architecture, arts, and etc. In condensed matter physics and materials science, we build atomic or spin arrangement up using symmetry, we can describe crystal and magnetic structure more effectively by compact ways. Physical properties, phase transition mechanism, ground state of Hamiltonian should be governed by crystal and magnetic symmetry. Recently, it is expected that axial vector interpretation of polyhedral or molecular rotation can allow odd-odd polynomial magnetoelastic coupling between crystal and magnetic order parameter.
Now, we are investing transition metal tri-fluoride and potassium superoxide.
For TiF3, we measured magnetic susceptibility, synchrotron XRD, high-resolution neutron diffraction. Still, we couldn't find long-range magnetic order with any further monoclinic distortion. Since TiF3 has peak broadening and oxidation problem, we are doing experiment again to confirm our observation.
For MnF3, we measured magnetic susceptibility and high-resolution neutron diffraction.
Since previous crystal model has poor RF factor and seems too low symmetry, we are looking for possible high symmetry crystal structure.
For KO2, we carried out low temperature synchrotron XRD and high-resolution neutron diffraction. We observed phase transition from phase 2 to phase 6. High-resolution neutron diffraction observed peak splitting.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
4: 遅れている
理由
Tri-flouride and Potassium superoxide are more air-sensitive than initial thought.
Sample freshness and quality affected crystal structure and magnetic properties a lot.
We need to carry out all sample preparation carefully in special environment as example of capillary sealing in synchrotron XRD. In addition, raw material's initial quality depends on each purchased bottle. These makes me difficult to keep same experimental conditions under consistent ways. In addition, initially we believed that crystal structure is well known. But, actually, KO2 crystal structure issue is not settle down.
Thus, instead of further study of magnetoelastic coupling, we need to study detail crystal structure step by step.
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| 今後の研究の推進方策 |
Now, we are mainly focusing to find odd-odd polynomial magnetoelastic coupling in polyhedral or molecular rotation systems. We are studying TiF3, MnF3, KO2 further. Also, we are looking for another candidates of novel magnetoelastic coupling.
For TiF3, we will repeat experiment carefully with another chemical company's sample.
For MnF3, we will search possible crystal structure through group-subgroup relation
For KO2, we are considering high intensity neutron diffraction, high resolution neutron diffraction under magnetic field.
After clarifying crystal structure of those materials, we will study magnetic structure, magnetoelastic coupling, and Landau phase transition theory.
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