| Project/Area Number |
26800174
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Condensed matter physics II
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| Research Institution | Tohoku University |
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Principal Investigator |
Tomiyasu Keisuke 東北大学, 理学(系)研究科(研究院), 助教 (20350481)
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| Project Period (FY) |
2014-04-01 – 2016-03-31
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| Project Status |
Completed (Fiscal Year 2015)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2015: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2014: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
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| Keywords | スピン分子 / フラストレーション / スピン格子結合 / スピン揺らぎ |
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| Outline of Final Research Achievements |
We carried on with the combination work of neutron scattering and ultrasound measurements on the frustrated spinel oxides with no magnetic order. In ZnFe2O4 without orbital degree of freedom, we observed a molecular spin excitation level at 10 meV (~ 100 K in energy). Elastic constant softens below 100 K, in which the thermal population of this level decreases. In MgV2O4 with orbital degree of freedom, the spin-orbital order vanishes by slightly excess Mg and molecular spin excitations were found. However, the energy structure is described as not a discrete level but a broad distribution from near zero to over 30 meV (~ 300 K in energy). The softening of elastic constant was confirmed below 150 K at least, which will be extended up to 300 K in principle in consideration of the spin excitation energy. Our studies experimentally show that the molecular spin excitations are accompanied with spin-lattice coupling and become source of anomalous phonon properties.
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