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JOURNAL OF SYNTHETIC CRYSTALS ›› 2022, Vol. 51 ›› Issue (11): 1858-1870.

• Research Articles • Previous Articles     Next Articles

Growth and Property of Aurivillius Structure Bi2MoxW1-xO6 Series Ferroelectric Functional Single Crystals

DING Xiaonan1, TIAN Xiangxin1, ZHAO Peng2, GAO Zeliang3, LIU Jingquan1   

  1. 1. School of Materials Science and Engineering, Linyi University, Linyi 276000, China;
    2. Sinoma Synthetic Crystals Co., Ltd., Beijing 100018, China;
    3. State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
  • Received:2022-07-11 Online:2022-11-15 Published:2022-12-07

Abstract: Synthesis conditions of Aurivillius structure Bi2MoxW1-xO6 series and the composition range of solid solution were explored by solid phase reaction method, and the flux growth system of Bi2MoxW1-xO6 crystal was explored. The structure, variable temperature dielectric property and resistivity of the crystal were measured and analyzed. Due to their large spontaneous polarization and high Curie temperatures, ferroelectric Aurivillius Bi2MoxW1-xO6 have attracted tremendous research attention in petroleum mining industries, communication equipments, meidcal ultrsonic diagnostics, structural health monitoring, et al. In this study, the composition variation range of n(Mo)∶n(W) ratio in Bi2MoxW1-xO6 solid solution were studied in detail through changing the sintering temperature and dewelling time. According to the synthetic results, the proportion(x) of Mo in the solid solution can be continuously tuned in the range of 0 to 1, and the pure ferroelectric phase of Bi2MoxW1-xO6 can be synthesized under different temperatures in the range of 500 ℃ to 870 ℃. Growth of the Bi2MoxW1-xO6 single crystals through the high temperature solution method were also explored systematically. By employing Li2B4O7-Bi2O3 (molar ratio 2∶1) as a flux, centimeter-sized Bi2WO6 single domain crystals were grown with the thickness of about 2 mm and the maximum dimension reaching as large as 40 mm. Centimeter-sized single domain crystals of Bi2Mo0.15W0.85O6 with the thickness of about 1 mm were also grown in n(Bi2O3)∶n(MoO3)∶n(WO3)∶n(Li2B4O7)=1∶1∶1∶1 (molar ratio) flux system. Structural refinement reveals that Bi2Mo0.15W0.85O6 crystallizes into the orthorhombic system, Aba2 (No.41) space group. Variable temperature dielectric measurements show that the dielectric constant ε33 increases from 70 of Bi2WO6 crystal to 102, and the temperature at which the dielectric relaxation occurs decreases from 430 ℃ of Bi2WO6 crystal to around 330 ℃. The temperature varying resistivity shows that the resistivity of Bi2WO6 and Bi2Mo0.15W0.85O6 crystals both decrease with the increase of temperature. Below 100 ℃, the resistivity of Bi2WO6 is higher than that of Bi2Mo0.15W0.85O6 crystal, and with the increase of temperature, the difference of resistivity between the two crystals is gradually narrowing.

Key words: Bi2MoxW1-xO6, Aurivillius structure, flux method, crystal structure, dielectric property, ferroelectric crystal, resistivity

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