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.

Crystal Structure and Microwave Dielectric Properties of Ca[(Li1/3Nb2/3)0.95Zr0.15]O3+δ Ceramics with Pr3+ Substitution at A-Site

2011 ◽  
Vol 181-182 ◽  
pp. 439-442
Author(s):  
Gang Xiong
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Quality Factor ◽  
Perovskite Structure ◽  
Single Phase ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric ◽  
Resonator Frequency ◽  
Orthorhombic Perovskite ◽  
A Site

Crystal structure and microwave dielectric properties of (Ca1-xPrx) [(Li1/3Nb2/3)0.95Zr0.15]3+δ (0.0≤x≤0.2, CPLNZ) ceramics were investigated. A single phase with orthorhombic perovskite structure was obtained at x=0.0~0.08. With an increase of Pr3+ content, the quality factor value firstly increased, and then began to decrease at x=0.06 due to a decrease of the degree of B-site 1:2 ordering. The variation of τf with tolerance factor was discussed. When x=0.06, the optimum microwave dielectric properties: the permittivity is 33.2, the quality factor is 17120 GHz，and the temperature coefficient of resonator frequency is −5.7×10−6/°C.

Microwave Dielectric Properties of Ca[(Li1/3Nb2/3)0.95Zr0.15]O3+δ Ceramics with Sm3+ Substitution at A-Site

2010 ◽  
Vol 663-665 ◽  
pp. 698-701
Author(s):  
Gang Xiong
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Quality Factor ◽  
Perovskite Structure ◽  
Single Phase ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric ◽  
Resonator Frequency ◽  
Orthorhombic Perovskite ◽  
A Site

Crystal structure and microwave dielectric properties of (Ca1-xSmx) [(Li1/3Nb2/3)0.95Zr0.15]3+δ(0.0≤x≤0.2,CSLNZ) ceramics were investigated. A single phase with orthorhombic perovskite structure was obtained at x=0.0~0.08. With an increase of Sm3+ content, the quality factor value firstly increased, and then began to decrease at x=0.03 due to a decrease of the degree of B-site 1:2 ordering. The variation of τf with tolerance factor was discussed. When x=0.05, the optimum microwave dielectric properties: the permittivity is 32.4，the quality factor is 16560GHz，and the temperature coefficient of resonator frequency is −6.3×10−6/°C。

Microwave Dielectric Properties of Ca[(Li1/3Nb2/3)0.95Zr0.05]O3−δ−xTiO2 Ceramics

2011 ◽  
Vol 181-182 ◽  
pp. 405-408
Author(s):  
Gang Xiong
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Perovskite Structure ◽  
Single Phase ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric ◽  
Orthorhombic Perovskite

Crystal structure and microwave dielectric properties of Ca [(Li1/3Nb2/3) 0.95Zr0.05]O3−δ−xTiO2(0≤x≤0.1) ceramics were investigated. A single phase with orthorhombic perovskite structure was obtained at x=0.02~0.1. With an increasing of Ti4+ content, the Qf value decreased due to a decrease of the degree of B-site 1:2 ordering. However, the τf value increased from-14.7ppm /°C to-6.9ppm/°C. When x=0.04, the optimum microwave dielectric properties: εr=31.1, Qf =21640GHz and τf =−8.8 ppm/°C.

Crystal Structure and Microwave Dielectric Properties of Ca[(Li1/3Nb2/3) 0.92Zr0.08]O3-δ−xTiO2 Ceramics

2010 ◽  
Vol 663-665 ◽  
pp. 515-518
Author(s):  
Gang Xiong
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Perovskite Structure ◽  
Single Phase ◽  
Microwave Dielectric Properties ◽  
Negative Direction ◽  
Microwave Dielectric ◽  
Orthorhombic Perovskite

Crystal structure and microwave dielectric properties of Ca[(Li1/3Nb2/3) 0.92Zr0.08]O3−δ−xTiO2(0≤x≤0.2) ceramics were investigated. A single phase with orthorhombic perovskite structure was obtained at x=0.0~0.1. With an increasing of Ti4+ content, the Qf value decreased due to a decrease of the degree of B-site 1:2 ordering. However, the τf value firstly increased from-14.2ppm /°C to -6.6ppm/°C, and then moved to the negative direction. When x=0.05, the optimum microwave dielectric properties: εr=32.8, Qf =19460GHz and τf =−8.3 ppm/°C.

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.

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.

Microwave Dielectric Properties of Ca1-x(Li1/2Sm1/2)xTiO3 Ceramics

2010 ◽  
Vol 105-106 ◽  
pp. 238-241 ◽  
Author(s):  
Yue Ming Li ◽  
Ting Ting Song ◽  
Fei Hu ◽  
Run Hua Liao ◽  
Bin Zhang
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric Ceramics ◽  
Fabrication Technique ◽  
Microwave Dielectric ◽  
Polarizability Effect ◽  
Orthorhombic Perovskite ◽  
Dielectric Ceramics ◽  
A Site

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.

Microwave dielectric properties of LiSmTa4O12 ceramics with A-site deficient perovskite structure

2020 ◽  
Vol 274 ◽  
pp. 128020
Author(s):  
Kangguo Wang ◽  
Huanfu Zhou ◽  
Xiaowen Luan ◽  
Sang Hu ◽  
Xianjie Zhou ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Perovskite Structure ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric ◽  
A Site

Effect of Nd2O3 on the Microwave Dielectric Properties of 0.67CaTiO3-0.33LaAlO3 Ceramics

2017 ◽  
Vol 726 ◽  
pp. 215-219 ◽  
Author(s):  
Zhan Ming Dou ◽  
Gan Wang ◽  
Juan Jiang ◽  
Tian Jin Zhang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Solid State ◽  
Solid State Reaction ◽  
Perovskite Structure ◽  
Single Phase ◽  
Microwave Dielectric Properties ◽  
Doping Amount ◽  
Microwave Dielectric

0.67CaTiO3-0.33LaAlO3 ceramics doped with Nd2O3 were prepared using a conventional two-step solid-state reaction, and the effect of Nd2O3 doping on the microwave dielectric properties were studied. A single phase of perovskite structure was confirmed with the Nd2O3 doping. The results showed that the addition of Nd2O3 obviously improved the density and Q×f values of CTLA ceramics. The dielectric constant were almost not affected and the τf values were close to zero with the increase of the doping amount. CTLA ceramics with 0.2 wt% Nd2O3 doping sintered at 1380 °C for 4 h exhibited the optimal microwave dielectric properties of εr = 45.36, Q×f = 37,890 GHz, τf = 7.80 ppm/°C.

scholarly journals Sintering behaviour and microwave dielectric properties of MgO-2B2O3-xwt%BaCu(B2O5)-ywt%H3BO3 ceramics

2021 ◽  
Author(s):  
Haiquan Wang ◽  
Shixuan Li ◽  
Kangguo Wang ◽  
Xiuli Chen ◽  
Huanfu Zhou
Keyword(s):  
Dielectric Properties ◽  
Bulk Density ◽  
Single Phase ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
X Ray Diffraction ◽  
Microwave Dielectrics ◽  
X Ray ◽  
Microwave Dielectric ◽  
Sintering Behaviour

AbstractThis study investigates the bulk density, sintering behaviour, and microwave dielectric properties of the MgO-2B2O3 series ceramics synthesised by solid-state reaction. According to the X-ray diffraction and microstructural analyses, the as-prepared MgO-2B2O3 ceramics possess a single-phase structure with a rod-like morphology. The effects of different quantities of H3BO3 and BaCu(B2O5) (BCB) on the bulk density, sintering behaviour, and microwave dielectric properties of the MgO-2B2O3 ceramics were investigated. Accordingly, the optimal sintering temperature was obtained by adding 30 wt% H3BO3 and 8 wt% BCB. We also reduced the sintering temperature to 825 °C. Furthermore, the addition of 40 wt% H3BO3 and 4 wt% BCB increased the quality factor, permittivity, and temperature coefficient of resonance frequency of MgO-2B2O3 to 44,306 GHz (at 15 GHz), 5.1, and −32 ppm/°C, respectively. These properties make MgO-2B2O3 a viable low-temperature co-fired ceramic with broad applications in microwave dielectrics.

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