Phase Relations and Microwave Dielectric Properties of ZnNb2O6–TiO2

2000 ◽  
Vol 15 (6) ◽  
pp. 1331-1335 ◽  
Author(s):  
Dong-Wan Kim ◽  
Deok-Yang Kim ◽  
Kug Sun Hong
Keyword(s):  
Solid Solution ◽  
Dielectric Properties ◽  
Quality Factor ◽  
Microwave Dielectric Properties ◽  
Relative Dielectric Constant ◽  
Phase Relations ◽  
Rutile Structure ◽  
Microwave Dielectric ◽  
Solid Solution Region ◽  
Solution Region

The phase relations and microwave dielectric properties of (1−x)ZnNb2O6–xTiO2 were investigated using x-ray powder diffraction and a network analyzer. Four phase regions were studied with increasing TiO2 mol% (x): columbite solid solution, ixiolite (ZnTiNb2O8) solid solution, mixture of ixiolite and rutile solid solutions, and rutile solid solution. It was suggested that the microwave properties depend on crystal structure rather than chemical composition. In the columbite solid solution region, an order–disorder transition was found with an increasing amount of TiO2, and the quality factor decreased sharply. ZnTiNb2O8 (x = 0.5), has a fully disordered structure and possesses a quality factor of 42,500, relative dielectric constant (εr) of 34.3, and temperature coefficient of resonant frequency (τf) of −52 ppm/°C. In the mixture region of ixiolite and rutile structure, τf was modified to around 0 ppm/°C.

Microwave dielectric properties of (1 − x)Cu3Nb2O8−xZn3Nb2O8 ceramics

2001 ◽  
Vol 16 (5) ◽  
pp. 1465-1470 ◽  
Author(s):  
Dong-Wan Kim ◽  
In-Tae Kim ◽  
Byungwoo Park ◽  
Kug Sun Hong ◽  
Jong-Hee Kim
Keyword(s):  
Solid Solution ◽  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Sintering Behavior ◽  
X Ray Diffraction ◽  
Two Phase ◽  
Sintering Aid ◽  
Microwave Dielectric ◽  
Solid Solution Region ◽  
Solution Region

The sintering behavior and microwave dielectric properties of (1 − x)Cu3Nb2O8−xZn3Nb2O8 have been investigated using dilatometry, x-ray diffraction, and a network analyzer. It was found that (1 − x)Cu3Nb2O8−xZn3Nb2O8 ceramics have a much lower melting temperature than Zn3Nb2O8 ceramics without Cu3Nb2O8 additives. Samples sintered at 900 °C for 2 h exhibited densities >97% of the theoretical density. Cu3Nb2O8 acts as a sintering aid. Two phase regions were identified with increasing Zn3Nb2O8 contents. A Cu3Nb2O8−Zn3Nb2O8 solid solution exists from 0 < x < 0.5 while a mixture of Cu3Nb2O8 and Zn3Nb2O8 exists from 0.5 < x < 1. The microwave dielectric properties correlated to the crystal structure. In Cu3Nb2O8−Zn3Nb2O8 solid solution region, the variation of dielectric properties could be explained by the structure distortion of Cu3Nb2O8 due to electronic anisotropies of Cu2+ cations.

Low Loss Dielectrics in Ba[(Mg1/3Ta2/3)1−xTix]O3 and Ba[(Mg1−xZnx)1/3Ta2/3]O3 Systems

2005 ◽  
Vol 20 (11) ◽  
pp. 2919-2926 ◽  
Author(s):  
Kuzhichalil Peethambaran Surendran ◽  
Mailadil Thomas Sebastian
Keyword(s):  
Solid Solution ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Quality Factor ◽  
Mole Fraction ◽  
Microwave Dielectric Properties ◽  
Quality Factors ◽  
Low Loss ◽  
Microwave Dielectric ◽  
Ti Substitution

The microwave dielectric properties of ceramics based on Ba[(Mg1/3Ta2/3)1−xTix]O3 (BMT-BT) and Ba[(Mg1−xZnx)1/3Ta2/3]O3 (BMT-BZT) were investigated as a function of composition x. In BMT-BT solid solution, the dielectric properties deteriorated with increasing concentration of Ti substitution at the B-site of BMT. A correlation was established between the quality factors of the solid solution phases and their tolerance factor. In BMT-BZT solid solution, where both the end compounds are ordered perovskites, the unit cell expands with increasing mole fraction of the Zn in Mg site of BMT while the dielectric constant increases monotonously from 24.8 (for BMT) to 29.7 (BZT). In BMT-BZT solid solution, the quality factor reaches a maximum (Qu·f = 109,900 GHz) for 60 mol/ of BZT.

Microwave Dielectric Properties of RENbO4 (RE=Y, Yb,Ce) Ceramics

2010 ◽  
Vol 434-435 ◽  
pp. 217-220 ◽  
Author(s):  
Zhi Li Zhang ◽  
Chun Xu ◽  
Qiu Ping Liu
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Quality Factor ◽  
Microwave Dielectric Properties ◽  
Relative Dielectric Constant ◽  
Dielectric Materials ◽  
Sintering Behavior ◽  
Microwave Dielectric ◽  
State Ceramic ◽  
Quality Factor Q

In the search of more microwave dielectric materials with high-quality factor (Qf ) and high relative dielectric constant (r), RENbO4 (where RE = Y, Ce, Yb) niobate ceramics were synthesized from a solid-state ceramic route, their sintering behavior and microwave dielectric properties were investigated. All of the RENbO4 ceramics formed a single-phase fergusonite-type structure (monoclinic, with space group I2/c), except CeNbO4. They all have an excellent quality factor and dielectric constant value in range of 20 – 28, and the inherent reasons were analyzed.

Micr owave Dielectric Properties of (1-x)CaTiO3-xNd(Mg1/2Ti1/2)O3 Ceramics System

2003 ◽  
Vol 783 ◽  
Author(s):  
Cheng-Liang Huang ◽  
Yuan-Bin Chen ◽  
Ching-Wen Lo
Keyword(s):  
Solid Solution ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Resonant Frequency ◽  
Quality Factor ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Compositional Range ◽  
Microwave Dielectric

ABSTRACTThe microwave dielectric properties of (1-x)CaTiO3-xNd(Mg1/2Ti1/2)O3 (0.1≤x≤1.0) have been investigated. The system forms a solid solution throughout the entire compositional range. The dielectric constant decreases from 152 to 27 as x varies from 0.1 to 1.0. In the (1-x)CaTiO3-xNd(Mg1/2Ti1/2)O3 system, the microwave dielectric properties can be effectively controlled by varying the x value. A maximum quality factor Qxf=43000GHz (where f is the resonant frequency) was achieved for samples with x=0.9, although the dielectric properties varied with sintering temperature. The Qxf value of (1-x)CaTiO3-xNd(Mg1/2Ti1/2)O3 almost increased up to 1500°C, after which it decreased. At 1400°C, 0.1CaTiO3-0.9Nd(Mg1/2Ti1/2)O3 ceramics gives a dielectric constant εr of 42, a Qxf value of 35000 (GHz) and a τf value of -10 (ppm/°C).

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.

Microwave dielectric properties of Ca[(Li1/3Nb2/3)1−xMx]O3−δ (M = Sn, Ti) ceramics

1999 ◽  
Vol 14 (9) ◽  
pp. 3567-3570 ◽  
Author(s):  
Ji-Won Choi ◽  
Chong-Yun Kang ◽  
Seok-Jin Yoon ◽  
Hyun-Jai Kim ◽  
Hyung-Jin Jung ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Resonant Frequency ◽  
Temperature Coefficient ◽  
Quality Factor ◽  
Single Phase ◽  
Microwave Dielectric Properties ◽  
Multiphase Materials ◽  
Microwave Dielectric ◽  
Orthorhombic Perovskite

The microwave dielectric properties of Ca[(Li1/3Nb2/3)1−xMx]O3−δ (M = Sn, Ti, 0 ≤ x ≤ 0.5) ceramics were investigated. In general, the ceramics prepared were multiphase materials. However, single-phase specimens having orthorhombic perovskite structure similar to CaTiO3 could be obtained in the vicinity of Sn = 0.2 to 0.3, and Ti = 0.2. As Sn concentration increased, the dielectric constant (εr) decreased and the quality factor (Q) significantly increased within the limited Sn concentration. As Ti concentration increased, the dielectric constant (εr) increased, the quality factor (Q) decreased, and the temperature coefficient of resonant frequency (τf) changed from a negative to positive value. The temperature coefficient of resonant frequency of 0 ppm/°C was realized at Ti = 0.2. The Q · fo value and εr for this composition were found to be 26100 GHz and 38.6, respectively.

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