2016 Fiscal Year Final Research Report
Bose-Einstein condensation in quantum spin system and supercurrent
| Project/Area Number |
26247058
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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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 | Tokyo Institute of Technology |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
栗田 伸之 東京工業大学, 理工学研究科, 助教 (80566737)
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| Project Period (FY) |
2014-04-01 – 2017-03-31
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| Keywords | 量子スピン系 / マグノン / ボース・アインシュタイン凝縮 / スーパーカレント / マグノンの結晶化 / 強磁場 / 新物質 |
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| Outline of Final Research Achievements |
We synthesized new dimerized magnet Ba2CoSi2O6Cl2 and determined its crystal structure. From high-magnetic field magnetization measurements, we observed quantum crystallization of magnons. The magnon crystallization is the opposite macroscopic quantum phenomenon to Bose-Einstein condensation (BEC) of magnons, and thus Ba2CoSi2O6Cl2 is a valuable experimental example. We also synthesized dimerized magnet Ba2CuSi2O6Cl2 that has a similar crystal structure as Ba2CoSi2O6Cl2 and elucidated its two-dimensional (2D) quantum magnetic properties. We investigated phase transition of quasi-2D ferromagnet K2CuF4 in the magnetic field, and verified the universality of quasi-2D BEC. We developed a new method to suppress magnetic torque in magnetic field using Ba2CoSi2O6Cl2 with large and anisotropic Van Vleck paramagnetism. Using this method, we succeeded in precise measurement of specific heat of CsFeBr3 in magnetic fields down to 100 mK, and verified the universality of 3D magnon BEC.
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| Free Research Field |
磁性物理学
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