Structural characteristics and microwave dielectric properties of In3+ and Nb5+ co-doped CaTiO3 ceramics

2017 ◽  
Vol 28 (8) ◽  
pp. 6301-6307 ◽  
Author(s):  
G. H. Chen ◽  
J. S. Chen ◽  
X. L. Kang ◽  
T. Yang ◽  
Y. Luo ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Structural Characteristics ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric ◽  
Co Doped

scholarly journals Structure, Defects and Microwave Dielectric Properties of Al-doped and Al/Nd Co-doped Ba4Nd9.33Ti18O54 Ceramics

2021 ◽  
Author(s):  
Weijia Guo ◽  
Zhiyu Ma ◽  
Yu Luo ◽  
Yugu Chen ◽  
Zhenxing Yue ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Resonant Frequency ◽  
Microwave Dielectric Properties ◽  
Relative Dielectric Constant ◽  
Doping Amount ◽  
Solid State Method ◽  
Depolarization Current ◽  
Structure Defects ◽  
Microwave Dielectric ◽  
Co Doped

Abstract Ba4Nd9.33Ti18-zAl4z/3O54 (BNT-A, 0 ≤ z ≤ 2) and Ba4Nd9.33+z/3Ti18-zAlzO54 (BNT-AN, 0 ≤ z ≤ 2) ceramics were prepared by solid state method, and the effects of the two doping methods on microwave dielectric properties were compared. As the doping amount z increased, the relative dielectric constant (εr) and the temperature coefficient of resonant frequency (τf) values of the ceramics decreased, and the quality factor (Q, usually expressed by Q×f, where f is the resonant frequency) of the ceramics obviously increased when z ≤ 1.5. With the same z value, the εr and Q×f values of Al/Nd co-doped ceramics are both higher than those of Al-doped ceramics. Rietveld refinement, Raman spectroscopy and thermally stimulated depolarization current (TSDC) technique were applied to clarify the relationship among the structure, defects and microwave dielectric properties. It is shown that the Q×f values of those ceramics were closely related to the strength of the A-site cation vibration and the concentration of oxygen vacancies (B). Excellent microwave dielectric properties of εr = 72.2, Q×f = 16480 GHz, and τf = +14.3 ppm/℃ were achieved in BNT-AN ceramics with z = 1.25.

Research on Sintering Dynamics and Microwave Dielectric Properties of Bi and Mn Doped Lead-Based Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 316-319 ◽  
Author(s):  
Jun Zhao ◽  
Shu Ping Gong ◽  
G. Xiong ◽  
X.H. Yu
Keyword(s):  
Grain Size ◽  
Dielectric Properties ◽  
Grain Growth ◽  
Volume Diffusion ◽  
Microwave Dielectric Properties ◽  
Doping Content ◽  
Mass Ratio ◽  
Microwave Dielectric ◽  
Mn Doped ◽  
Co Doped

The sintering dynamics, microstructures and microwave dielectric properties of Bi2O3 and MnO2 co-doped [(Pb,Ca) La](Fe,Nb)O3 (PCLFN) ceramics were investigated. Bi2O3 and MnO2 dopants effectively enhanced bulk densities and reduced sintering temperatures by about 100~140°C. Sintering procedure had significant effect on grain size and porosities of ceramics. Investigation of microstructures revealed that the grain growth was controlled by either volume diffusion or second-order interface mechanism in present ceramics. The potential microwave dielectric properties of εr=91.1,Qf=4870GHz and τf=18.5ppm/°C could be obtained when the mass ratio of Bi2O3/MnO2 (k) was 1, the doping content w=1wt% and sintered at 1050°C for 4h.

Microwave dielectric properties of B and N co-doped SiC nanopowders prepared by combustion synthesis

2019 ◽  
Vol 777 ◽  
pp. 1039-1043 ◽  
Author(s):  
Zi Yang ◽  
Zhimin Li ◽  
Tao Ning ◽  
Maolin Zhang ◽  
Yangxi Yan ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Combustion Synthesis ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric ◽  
Co Doped

DEPENDENCE OF MICROWAVE DIELECTRIC PROPERTIES ON STRUCTURAL CHARACTERISTICS OF ILMENITE, TRI-RUTILE AND WOLFRAMITE CERAMICS

2011 ◽  
Vol 01 (01) ◽  
pp. 127-134 ◽  
Author(s):  
EUNG SOO KIM ◽  
CHANG JUN JEON
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Structural Characteristics ◽  
Microwave Dielectric Properties ◽  
Oxygen Octahedra ◽  
Microwave Frequencies ◽  
Microwave Dielectric ◽  
Oxygen Ion ◽  
Octahedral Cation ◽  
Octahedral Distortion

Effects of crystal structures on dielectric properties of ATiO 3 (trigonal ilmenite), ATa 2 O 6 (tetragonal tri-rutile) and AWO 4 (monoclinic wolframite) (A = Ni, Mg, Co) ceramics with A- and B-site oxygen octahedra were investigated at microwave frequencies. The dielectric constant (K) of the specimens was affected by the dielectric polarizabilities of composition and cation bond valence between octahedral cation and oxygen ion per molar volume (V m ). The quality factor (Qf) of ATiO 3 was appreciably larger than those of ATa 2 O 6 and AWO 4 due to the different sharing types of oxygen octahedra. The temperature coefficient of resonant frequency (TCF) of the specimens was dependent on the octahedral distortion per V m .

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