Growth of Pb((Zn1/3Nb2/3)0.91Ti0.09)O3Single Crystals Using an Allomeric Seed Crystal and Their Electrical Properties
| Autor: | Zhiwen Yin, Tianhou He, Haosu Luo, Haiqing Xu, Bijun Fang |
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| Rok vydání: | 2004 |
| Předmět: | |
| Zdroj: | Journal of the American Ceramic Society. 87:991-995 |
| ISSN: | 1551-2916 0002-7820 |
| Popis: | Single crystals of Pb((Zn 1/3 Nb 2/3 ) 0.91 Ti 0.09 )O 3 (PZNT 91/9), 28 mm in diameter and 30 mm in length, have been successfully grown using a modified Bridgman technique with an allomeric seed crystal. X-ray fluorescence analysis (XRFA) measurement confirms that the effect of segregation is not serious. The segregation coefficient k for PbTiO 3 content during crystal growth is 0.99, which causes some fluctuation in the composition along the growth direction. The fluctuation of composition and the complicated domain structure cause a variation of electric properties. Dielectric measurement indicates that PZNT 91/9 crystals exhibit an almost normal ferroelectric phase transition at ∼183°C from the tetragonal phase to the cubic phase. In addition, a weak frequency-dependent ferroelectric-ferroelectric phase transition is observed at ∼85°C, which is attributed to partial conversion of the rhombohedral phase to a tetragonal phase. The dielectric thermal hysteresis behavior and the existence of polarization above the Curie temperature verify that the phase transitions at ∼85° and 183°C are first order with a slight diffuse character and first order, respectively. It is demonstrated that the effects of segregation can be decreased and the homogeneity of the obtained PZNT 91/9 single crystals can be improved by optimizing growth parameters. |
| Databáze: | OpenAIRE |
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