检索结果-南通市图书馆

Microwave dielectric properties and microstructure of a new kind Eu-based Eu(Mg_(0.5)Ti_(0.5))O_3 ceramic

Rare Metals 2018年第11期37卷 913-918页

作者： Tao Shi Jing Zhu National Center for Electron Microscopy in Beijing Tsinghua University School of Materials Science and Engineering Tsinghua University The State Key Laboratory of New Ceramics and Fine Processing Tsinghua University Laboratory of Advanced Materials Tsinghua University

A new Eu-based microwave dielectric ceramic,Eu(MgTi)O(EMT for short), was prepared through conventional solid-state reactions. The EMT ceramics were well densified at 1425 ℃ and exhibit good microwave dielectric properties with permittivity of 23.92, high quality factor(Q*f) of 66,957 GHz at 8.93 GHz and relatively low-temperature coefficient of resonant frequency of-20.3 10/K. Additionally, the variations of dielectric constants among Ln(MgTi)O(Ln represents rare earth elements, LMT) compounds were analyzed. Ionic radii of Ln, associated with the tolerance factors of the perovskite structure of LMT, were investigated to be the key factor to influence the permittivity. These results indicate that EMT ceramics might be one of the promising candidates as microwave resonators.

关键词： Microwave dielectrics Eu(Mg_(0.5)Ti_(0.5))O_3 complex perovskite Solid-state reactions

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of Sn^(4+) B-Site Substitution on the Microstructure and Dielectric Properties of Ba(Mg_(1/3)Ta_(2/3))O_3 Microwave Ceramics

引用

Journal of Materials Science & Technology 2005年第5期21卷 773-775页

作者： Shunhua WU Guoqing WANG, Shuang WANG and Dandan LIUInstitute of Electronics and Information Engineering, Tianjin University, Tianjin 300072, China Institute of Electronics and Information Engineering Tianjin University Tianjin 300072 China

The effect of Sn^4＋（BaSnO3） B-site substitution on the microstructure and dielectric properties of Ba（Mg1/3Ta2/3）O3 microwave ceramics was investigated. X-ray diffraction shows that a complex perovskite material Ba（Mg1/3Ta2/3）O3 was prepared. As Sn^4＋ content x increases in the （1-x） Ba（Mg1/3Ta2/3）O3-xBaSnO3 （x=0.00～0.20） system, the dielectric constant generally keeps unchanged, while TCF changes from positive to negative. Although the addition of Sn^4＋ reduces the ordering degree, Q f0 is still increased when the ceramics density increases. This trend implies that Q f0 of this system is mostly determined by ceramics density rather than ordering degree. After sintering at 1500℃ for 3 h, the system with x=0.15 was found to have excellent dielectric properties as follows：ε≈25, Q f0≥300,000 GHz at 7 GHz, TCF=-0.6×10^-6/℃.

关键词： Ba(Mg1/3Ta2/3)O3 complex perovskite Microwave Dielectric properties

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Modification of physical properties of Ba(Ni_(1/3)Nb_(2/3))O_(3) ceramics through ordered domain engineering

引用

Journal of Materiomics 2022年第4期8卷 815-822页

作者： Rui Da Shi Mei Ying Liu Xiao Li Zhu Xiang Ming Chen Laboratory of Dielectric Materials School of Materials Science and EngineeringZhejiang University38 Zheda RoadHangzhou310027China

Ordered domain engineering has been further developed for modifying and improving physical prop-erties in complex perovskite ceramics. In the present work, Ba(Ni_(1/3)Nb_(2/3))O_(3) ceramic is taken as a typicalexample for ordered domain engineering, in which the sintering temperature lies above the order-disorder transition temperature. Though the well-ordered structure could not be obtained in as-sintered samples, high ordering degree could be achieved together with preferred ordered domainstructures in Ba(Ni_(1/3)Nb_(2/3))O_(3) ceramics through long-time annealing, and subsequently the physicalproperties such as electrical resistivity, thermal conductivity, dielectric strength and energy storagedensity are significantly enhanced, where the ordering degree, ordered domain structure and ordereddomain boundary play the critical rules. The present work provides an effective approach for developingcomplex perovskite dielectric ceramics with superior physical properties.

关键词： complex perovskite Ordered domain engineering Electrical resistivity Thermal conductivity Dielectric strength

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Order-Disorder Phase Transition and Dielectric Mechanism in Relaxor Ferroelectrics

引用

Tsinghua Science and Technology 2001年第2期6卷 97-108页

作者：吴忠庆刘志荣顾秉林 Department of Physics Tsinghua University Beijing 100084 China

An overview is presented on the order-disorder structural transitions and the dielectric mechanism in the complex-perovskite type relaxor ferroelectrics, i.e., the relaxors. Emphasis is put on the theoretical understanding of the structural transitions, the macroscopic dielectric properties, and the relationship between them. The influences of the composition, the temperature, and the atomic interactions on the order-disorder microstructures can be well understood in the cluster-variation-method calculations. The criterion drawn from theoretical analysis is successful in predicting the order-disorder structure of relaxors. Among various physical models about relaxors, the dipole glassy model that described the dielectric response as the thermally activated flips of the local spontaneous polarization under random interactions is discussed in details. The Monte Carlo simulation results of this model are consistent with the linear and nonlinear experiments of relaxors.

关键词： order-disorder transition relaxor ferroelectrics complex perovskite

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：