Effect of bond valence on microwave dielectric properties of (Pb1−xCax)(Mg0.33Ta0.67)O3 ceramics

2001 ◽  
Vol 16 (3) ◽  
pp. 817-821 ◽  
Author(s):  
Heung Soo Park ◽  
Ki Hyun Yoon ◽  
Eung Soo Kim
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Bond Valence ◽  
Negative Deviation ◽  
Complex Perovskite ◽  
Microwave Frequencies ◽  
Microwave Dielectric ◽  
Dielectric Polarizability ◽  
A Site ◽  
The Relationship

The relationship between the dielectric properties of the complex perovskite (Pb1−xCax)(Mg0.33Ta0.67)O3 ceramics, where 0.45 ≤ × ≤ 0.60, and the dielectric polarizability, related to bond valences of A-site ions, was investigated at microwave frequencies. As the Ca content (x) increased, the deviation of the observed dielectric polarizabilities, calculated by the Clausius–Mosotti equation from the theoretical values calculated by the additivity rule of dielectric polarizability, decreased from −3% to −0.69%. It was found that this deviation was related to the bond valence of the A-site. Smaller negative deviation corresponded to the cations with lower bond valence, and larger negative deviation corresponded to the cations with higher bond valence. Also, the temperature coefficient of resonant frequency (TCF) was affected by the bond valence of the A-site, and then TCF decreased with decreasing bond valence of the A-site in ABO3 perovskite compounds.

Understanding microwave dielectric properties of Pb-based complex perovskite ceramics via bond valence

2004 ◽  
Vol 30 (8) ◽  
pp. 2247-2250 ◽  
Author(s):  
Yong S. Cho ◽  
Ki Hyun Yoon ◽  
Byoung Duk Lee ◽  
Hong Ryul Lee ◽  
Eung Soo Kim
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Bond Valence ◽  
Complex Perovskite ◽  
Microwave Dielectric ◽  
Perovskite Ceramics

Microwave Dielectric Properties of Ca[(Li1/3Nb2/3)0.95Zr0.15]O3+δ Ceramics with Ba2+ Substitution at A-Site

2007 ◽  
Vol 336-338 ◽  
pp. 196-198
Author(s):  
Dong Xiang Zhou ◽  
G. Xiong ◽  
Shu Ping Gong ◽  
Jun Zhao ◽  
M.Z. Hu ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Perovskite Structure ◽  
Single Phase ◽  
Microwave Dielectric Properties ◽  
Bond Valence ◽  
Microwave Properties ◽  
Microwave Dielectric ◽  
Orthorhombic Perovskite ◽  
A Site

The microwave properties of (Ca1-xBax)[(Li1/3Nb2/3)0.95Zr0.15]O3+δ(0.0≤x≤0.2, CBLNZ) ceramics were investigated. A single phase with orthorhombic perovskite structure was obtained at x = 0.0 − 0.025. Both the εr and Qf value firstly increased with increasing Ba2+ content, and then began to decrease at x = 0.025. The τf value increased from −9.4 ppm/°C at x=0.0 to 18ppm/°C at x=0.2, which could be explained by the decrease of B-site bond valence in perovskite structure.

Microwave Dielectric Properties of Ca(Li1/3Nb2/3)O3-δ Ceramics with ZnO Additive

2011 ◽  
Vol 687 ◽  
pp. 144-150
Author(s):  
Ji Hong Liao ◽  
Ying Dai ◽  
Wen Chen ◽  
Lian Xiang Tan ◽  
Shao Hua Qu
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Complex Perovskite ◽  
Dielectric Characteristics ◽  
X Ray ◽  
Microwave Dielectric ◽  
State Ceramic ◽  
Solid State Ceramic Route ◽  
The Relationship

The complex perovskite compound Ca(Li1/3Nb2/3)O3-δ(CLN) ceramics have received much attention due to the superior properties and relatively low sintering temperature 1150°C. In order to further low the sintering temperature of the CLN ceramics, enhance the Q · f values and other dielectric properties, the effects of the additive ZnO on the sinterability and dielectric properties of the CLN have been investigated. The CLN ceramics were prepared by conventional solid state ceramic route. With the addition of 1.0 wt% ZnO, the sintering temperature of Ca(Li1/3Nb2/3)O3-δ(CLN) ceramics was effectively reduced from 1150◦C to 1090◦C，and the Q · f value was increased from 18920 to 20950 GHz (at 7.09 GHz). It also possesses compatible dielectric constant εrof 27.8 and τfvalue of -23.57 ppm/◦C. While with the addition of 1.25 wt% ZnO, the Q · f value of Ca(Li1/3Nb2/3)O3-δ(CLN) ceramics sintered at 1150◦C for 3 hours was increased significantly to 32150 GHz (at 7.09 GHz), εrof 28.3 and τfvalue of -18.55 ppm/◦C. The relationship between microstructure and microwave dielectric characteristics was studied using X-ray diffractometer and Scanning electron microscope.

Effect of A-Site Non-stoichiometry on Structure and Microwave Dielectric Properties of Ca x (Li0.36Nd0.36Bi0.14Na0.14)TiO3 Ceramics

2017 ◽  
Vol 47 (1) ◽  
pp. 285-291
Author(s):  
Xiao Liu ◽  
Changlai Yuan ◽  
Fenghua Luo ◽  
Xinyu Liu ◽  
Yuanlei Zhen ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric ◽  
A Site

Dielectric Properties of a New Ceramic System (1-x)(Mg0.95Zn0.05)2TiO4-x(Ca0.8Sr0.2)TiO3 at Microwave Frequencies

2020 ◽  
Vol 830 ◽  
pp. 37-42
Author(s):  
Shih Sheng Liu ◽  
Shiuan Ho Chang ◽  
Yuan Bin Chen
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Second Phase ◽  
X Ray Diffraction ◽  
Low Loss ◽  
Microwave Frequencies ◽  
Solid State Route ◽  
Microwave Dielectric ◽  
System 1 ◽  
Quality Factor Q

The microwave dielectric properties and microstructures of the (1-x)(Mg0.95Zn0.05)2TiO4-x (Ca0.8Sr0.2)TiO3 ceramics prepared using the conventional solid-state route were investigated. The structure and microstructure were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Ilmenite-structured (Mg0.95Zn0.05)TiO3 was detected as a second phase. The coexistence of the second phase, however, did not degrade the dielectric properties of the specimen because the phases were compatible. At x = 0.07, a dielectric constant (εr) of ~17.86, a quality factor (Q×f) value of ~ Q×f~133,600 Hz (at 10 GHz), and a temperature coefficient of resonant frequency (τf) of ~ –5ppm/°Cwere obtained for 0.93(Mg0.95Zn0.05)2TiO4-0.07(Ca0.8Sr0.2)TiO3 ceramic sintered at 1240°C for 4 hr. The dielectric is proposed as a candidate material for low-loss microwave and millimeter wave applications.

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