2016 Fiscal Year Final Research Report
Single Crystal Growth of KF-Substituted Barium Titanate and the Physical Properties near the Critical Point
| Project/Area Number |
25400329
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Condensed matter physics I
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| Research Institution | Shimane University |
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Principal Investigator |
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| Project Period (FY) |
2013-04-01 – 2017-03-31
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| Keywords | チタン酸バリウム / KF添加 / 単結晶 / 誘電率 / 自発分極 / 三重臨界点 / 臨界終点 / 相図 |
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| Outline of Final Research Achievements |
Single crystals of BaTiO3 with different KF composition x were systematically grown. Especially, focusing on x = 0.1 where the dielectric constant becomes the largest, we developed a method for growing the large single crystal. The temperature dependence of the dielectric constant, the spontaneous polarization and the temperature dependence of the dielectric constant under the application of the dc electric field were precisely investigated using the high quality single crystal
Experimental results show that x = 0.1 composition is near the tri-critical point, as we expected. The critical end point indicating the transition from the first order transition to the second order transition induced by applying the direct electric field is generated at the critical electric field Ec = 10 kV / cm at x = 0, but Ec decreases with increasing the KF composition; Ec becomes 0 at x=0.1 . A three-dimensional phase diagram of composition - electric field - temperature in this system was clarified.
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| Free Research Field |
誘電体物性実験
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