Growth and properties of Ca_0.28Ba_0.72Nb₂O₆ single crystals

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• 作者：Song ; Hualong ; Zhang ; Huaijin ; Xu ; Xiangang ; Hu ; Xiaobo ; Cheng ; Xiufeng ; Wang ; Jiyang ; Jiang ; Minhua
• 关键词：A. Inorganic compounds ; B. Crystal growth ; C. X-ray diffraction ; D1. Specific heat ; D2. Thermal expansion
• 刊名：Materials Research Bulletin
• 出版年：2005
• 出版时间：April 20, 2005
• 年：2005
• 卷：40
• 期：4
• 页码：643-649
• 全文大小：165 K

文摘

Calcium barium niobate Ca_0.28Ba_0.72Nb₂O₆ (CBN-28) crystals were successfully grown by the Czochralski method. X-ray powder diffraction experiments indicated that CBN single crystals are tetragonal with a = 12.432(±0.002) Å and c = 3.957(±0.001) Å, which have almost the same structure as the Sr_0.50Ba_0.50Nb₂O₆ (SBN-50) crystal. The thermal expansion coefficient perpendicular to Z-direction had been measured to be 1.25 × 10⁻⁵ K⁻¹ between 293.15 and 572.15 K, and along Z-axis was negative between 298.15 and 543.15 K. The specific heat of the crystal had been measured by the differential scanning calorimetric experiments. The transmittance spectra from 200 to 3200 nm were also measured. The measured temperature dependence of dielectric constants showed that the Curie temperature of the CBN-28 crystals is 260 °C, which is about 200 °C higher than that of the (SBN) crystal.