• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control >Dielectric response and specific heat studies of Cd2Nb2O7 ceramics obtained from mechano-synthesized nanopowders
【24h】

Dielectric response and specific heat studies of Cd2Nb2O7 ceramics obtained from mechano-synthesized nanopowders

机译：机械合成纳米粉制得的Cd2Nb2O7陶瓷的介电响应和比热研究

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Cd2Nb2O7 is still an interesting ferroelectric material because of its high permittivity value at helium temperatures and a variety of dielectric relaxation processes, the origin of which is still puzzling. We prepared hot-pressed ceramics, with grain sizes from 100 to 150 nm, obtained from Cd2Nb2O7 nanopowders synthesized by high-energy milling of CdO and Nb2O5 and studied their dielectric response and thermal properties. The nanoceramics were characterized by X-ray diffraction and their dielectric properties were measured at temperatures from 4K to 575K. Dielectric response of the nanoceramics was found to consist of a huge anomaly at ~150K with complex dielectric absorption and three relaxation processes apparent in frequency and temperature dependences of the imaginary part of permittivity in the temperature range from 18K to 145K. The anomaly at ~150K is related to overlapping contributions from the Curie point (shifted downward because of the size effect) and a dielectric relaxation process. The behavior of three relaxation modes observed at temperatures below 145K is discussed, based on the model proposed by Malcherek of polar nanoregions in the orthorhombic phase of Cd2Nb2O7 and the theory of dielectric response of ferroelectric relaxors by Bokov and Ye.
机译：Cd2Nb2O7仍然是一种有趣的铁电材料，因为它在氦气温度下的介电常数很高，并且介电弛豫过程多种多样，其起源仍然令人费解。我们准备了由CdO和Nb2O5的高能研磨合成的Cd2Nb2O7纳米粉获得的晶粒尺寸为100至150 nm的热压陶瓷，并研究了它们的介电响应和热性能。通过X射线衍射表征纳米陶瓷，并在4K至575K的温度下测量其介电性能。发现纳米陶瓷的介电响应包括在〜150K处的一个巨大异常，具有复杂的介电吸收和三个弛豫过程，在温度和介电常数的虚部在18K到145K的温度和频率之间存在明显的三个弛豫过程。 〜150K处的异常与居里点的重叠贡献（由于尺寸效应而向下移动）和介电弛豫过程有关。基于Cad2Nb2O7正交相的极性纳米区域的Malcherek提出的模型，以及Bokov和Ye的铁电弛豫材料的介电响应理论，讨论了在低于145K的温度下观察到的三种弛豫模式的行为。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号