Modification of Ba6-3xSm8+2xTi18O54 (x=2/3)Microwave Dielectric Ceramics by Nd/Bi Co-Substitution on A-Site

Author(s):  
N. Qin ◽  
X.M. Chen
2007 ◽  
Vol 280-283 ◽  
pp. 57-60 ◽  
Author(s):  
N. Qin ◽  
X.M. Chen

Ba6-3xSm8+2xTi18O54 microwave dielectric ceramics were modified by Nd/Bi co-substitution for Sm on A-site. According to XRD and SEM analysis, a single-phase solid solution with new tungsten bronze-type structure was formed in low-Bi-substituted region. Bi was effective on increasing dielectric constant, while led to a decreased Qf value and an increased negative tf. The co-substituting approach exhibited the advantage in improving e and compensating Qf and tf value.


2010 ◽  
Vol 105-106 ◽  
pp. 238-241 ◽  
Author(s):  
Yue Ming Li ◽  
Ting Ting Song ◽  
Fei Hu ◽  
Run Hua Liao ◽  
Bin Zhang

Ca1-x(Li1/2Sm1/2)xTiO3 microwave dielectric ceramics in the x range of 0.70 ~ 0.80 were prepared by conventional ceramics fabrication technique. The crystal structure, microstructure and microwave dielectric properties were investigated. The results showed that a single orthorhombic perovskite structure formed within this x range, and the substitution of (Li1/2Sm1/2)2+ ion for Ca2+ ion in A-site has a significant influence on the microwave dielectric properties of the ceramics. With the increase of substitution of (Li1/2Sm1/2)2+ ion with 0.75, the temperature coefficient of resonant frequency τf reaches zero, and it could be attributed that the Sm and Li have a polarizability effect according to its microstructure. The Ca0.25(Li1/2Sm1/2)0.75TiO3 ceramic had a good performance with microwave dielectric properties of τf = 0 ppm/°C, εr = 105.83, and Qf = 3170 GHz.


2014 ◽  
Vol 2 (35) ◽  
pp. 7364-7372 ◽  
Author(s):  
Jing Guo ◽  
Clive A. Randall ◽  
Gaoqun Zhang ◽  
Di Zhou ◽  
Yuyan Chen ◽  
...  

A series of A-site defective scheelite (Ca1−3xBi2xΦx)MoO4 compositions were formed as a solid solution, and their local structures indicate that Bi–O polyhedrons become more distorted with x value.


2010 ◽  
Vol 25 (3) ◽  
pp. 332-336
Author(s):  
Zheng-Dong LU ◽  
Chun-Ying SHEN ◽  
Liang LI ◽  
Jian YANG ◽  
Tai QIU

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