Crystal Structure and Microwave Dielectric Properties of BanLa4Ti3+nO12+3n Homologous Compounds with High Dielectric Constant and High Quality Factor

2008 ◽  
pp. 75-80 ◽  
Author(s):  
H. Ohsato ◽  
Y. Tohdo ◽  
K. Kakimoto ◽  
T. Okawa ◽  
H. Okabe
Keyword(s):  
Crystal Structure ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Quality Factor ◽  
High Dielectric Constant ◽  
Microwave Dielectric Properties ◽  
High Quality ◽  
Microwave Dielectric ◽  
Homologous Compounds ◽  
High Dielectric

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.

Sintering Behavior and Microwave Dielectric Properties of Li2O-B2O3-SiO2 Doped 0.67CaTiO3-0.33LaAlO3 Ceramics

2017 ◽  
Vol 726 ◽  
pp. 220-224
Author(s):  
Gan Wang ◽  
Juan Jiang ◽  
Zhan Ming Dou ◽  
Fan Fan Ning ◽  
Er Tian Zhang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Quality Factor ◽  
Amorphous State ◽  
Microwave Dielectric Properties ◽  
Sintering Behavior ◽  
Low Temperature Sintering ◽  
Microwave Dielectric ◽  
Structure Surface ◽  
Sintering Method

A low temperature sintering method was used to avoid the relatively high sintering temperatures typically required to prepare 0.67CaTiO3-0.33LaAlO3 (CTLA) ceramics. 0.67CaTiO3-0.33LaAlO3 ceramics doped with Li2O-B2O3-SiO2 (LBS) were prepared by a conventional two-step solid-state reaction process. The sintering behavior, crystal structure, surface morphology, and microwave dielectric proprieties of the prepared ceramics were studied. As the small amount of LBS content increased, the small amount of liquid phase formed in an amorphous state around the surface of the grain boundaries. With the increase the content of LBS glass, the quality factor (Q×f) value decreased. CTLA+0.05 wt.% LBS ceramics sintered at 1320°C for 4h exhibited the optimal microwave dielectric properties of dielectric permittivity (εr) = 45.02, quality factor (Q×f) = 37400 GHz, and temperature coefficient of resonant frequency (τf) = 9.84 ppm/°C. .

Sintering characteristics and microwave dielectric properties of 0.5(Ca0.7Nd0.2)TiO3–0.5(Li0.5Nd0.5)TiO3 ceramics with La2O3–B2O3–CaO–P2O5 additive

2021 ◽  
Author(s):  
Jiawen Shi ◽  
Xingyu Chen ◽  
Weijun Zhang ◽  
Haijun Mao ◽  
Fenglin Wang ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
High Dielectric Constant ◽  
Sintering Temperature ◽  
Glass Ceramics ◽  
Microwave Dielectric Properties ◽  
Low Loss ◽  
Sintering Aid ◽  
Microwave Dielectric ◽  
Sintering Characteristics ◽  
High Dielectric

In this paper, the effects of glass-ceramics sintering aid, La2O3–B2O3–CaO–P2O5 (LBCP), on the sinterability, microstructure, and microwave dielectric properties of 0.5(Ca[Formula: see text]Nd[Formula: see text]TiO3–0.5(Li[Formula: see text]Nd[Formula: see text]TiO3 (CNT–LNT) ceramic have been investigated. The results indicated that LBCP glass-ceramics has good wettability to CNT–LNT (contact angle at 980[Formula: see text]C is 31.9[Formula: see text]), and it can be used as an effective sintering aid to reduce the sintering temperature of CNT–LNT ceramic from 1300[Formula: see text]C to 980[Formula: see text]C. LBCP glass-ceramics did not change the main crystal phase (perovskite structure) of the sample, but a small amount of LaBO3 and LaPO4 phases was precipitated. Since the LaBO3 and LaPO4 phases are low-loss phases, it is believed that the crystal phases can improve the dielectric properties of the sample, especially the dielectric loss. The samples with 10 wt.% of glass additive sintered for 4 h at 980[Formula: see text]C exhibit the optimized properties: a high dielectric constant of 80.8 and a [Formula: see text] value of 2031 GHz. The high [Formula: see text] and [Formula: see text] value, coupled with a relatively low sintering temperature, suggest that the optimized compositions have the potential to be used in microwave low-temperature co-fired ceramics applications.

Effects of CuO and V2O5 Addition on Sintering Behavior and Microwave Dielectric Properties of (1-x)Ca2P2O7-xTiO2

2007 ◽  
Vol 336-338 ◽  
pp. 279-282
Author(s):  
In Sun Cho ◽  
Sang Gu Kang ◽  
Dong Wan Kim ◽  
Kug Sun Hong
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Resonant Frequency ◽  
Temperature Coefficient ◽  
Quality Factor ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Sintering Behavior ◽  
Microwave Dielectric

The effects of CuO and V2O5 addition on sintering behaviors and microwave dielectric properties of 0.7Ca2P2O7-0.3TiO2 ceramics were investigated. With CuO and V2O5 addition, the sintering temperature of 0.7Ca2P2O7-0.3TiO2 can be effectively reduced from 1150 to 950oC. The dielectric constant of the low fired 0.7Ca2P2O7-0.3TiO2 ceramics was not significantly changed while the quality factor was affected by additives. The temperature coefficient of resonant frequency value was increased in negative value with the additive contents. V2O5 and CuO additives effectively improved the densification and dielectric properties of 0.7Ca2P2O7-0.3TiO2 ceramics. The correlation between the phase constituents and the dielectric properties was investigated with additive contents.

Preparation and Microwave Dielectric Properties of xBaZn2Ti4O11-(1-x)BaNd2Ti4O12 Ceramics

2017 ◽  
Vol 726 ◽  
pp. 210-214
Author(s):  
Xu Wang ◽  
Ren Li Fu ◽  
Yue Xu ◽  
Yang Yang ◽  
Jun De Cai ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Phase System ◽  
Microwave Ceramics ◽  
Two Phase ◽  
Microwave Dielectric ◽  
X Band ◽  
High Dielectric

xBaZn2Ti4O11–(1-x)BaNd2Ti4O12 (x = 0.18–0.30) ceramics were prepared by solid-state reaction method and their microwave dielectric properties were investigated with the purpose of finding a microwave ceramics with high dielectric constant (εr), high quality factor (Q×f ) and zero temperature coefficient of resonant frequency (τf).The two phase system BaZn2Ti4O11–BaNd2Ti4O12 affected the unit cell volume and the microstructure, the microwave dielectric properties (εr, Q×f, τf). As increasing x from 0.18 to 0.30, the main phase composition was BaNd2Ti4O12. Therefore, the εr decreased from 64.9 to 60.3 and the Q×f values raised from 11,350GHz to 13,210GHz, and the τf values decreased from 7ppm/° to -5ppm/°.The 0.22BaZn2Ti4O11–0.78BaNd2Ti4O12 ceramics sintered at 1250°C for 4 h displayed the best dielectric constant εr,Q×f and τf, as 63.9, 12380 GHz and-0.1 ppm/° respectively.

scholarly journals A low-firing melilite ceramic Ba2CuGe2O7 and compositional modulation on microwave dielectric properties through Mg substitution

2020 ◽  
Author(s):  
Changzhi Yin ◽  
Zezong Yu ◽  
Longlong Shu ◽  
Laijun Liu ◽  
Yan Chen ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Resonance Frequency ◽  
Temperature Coefficient ◽  
Quality Factor ◽  
Relative Permittivity ◽  
Microwave Dielectric Properties ◽  
Sintering Behavior ◽  
Magnesium Doping ◽  
Microwave Dielectric

AbstractA melilite Ba2CuGe2O7 ceramic was characterized by low sintering temperature and moderate microwave dielectric properties. Sintered at 960 °C, the Ba2CuGe2O7 ceramic had a high relative density 97%, a low relative permittivity (εr) 9.43, a quality factor (Q×f) of 20,000 GHz, and a temperature coefficient of resonance frequency (τf) −76 ppm/°C. To get a deep understanding of the relationship between composition, structure, and dielectric performances, magnesium substitution for copper in Ba2CuGe2O7 was conducted. Influences of magnesium doping on the sintering behavior, crystal structure, and microwave dielectric properties were studied. Mg doping in Ba2CuGe2O7 caused negligible changes in the macroscopic crystal structure, grain morphology, and size distribution, while induced visible variation in the local structure as revealed by Raman analysis. Microwave dielectric properties exhibit a remarkable dependence on composition. On increasing the magnesium content, the relative permittivity featured a continuous decrease, while both the quality factor and the temperature coefficient of resonance frequency increased monotonously. Such variations in dielectric performances were clarified in terms of the polarizability, packing fraction, and band valence theory.

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.

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