Composition dependence of dielectric properties of (Ta2O5)1−x(TiO2)x polycrystalline ceramics

2003 ◽  
Vol 99 (1-3) ◽  
pp. 221-225 ◽  
Author(s):  
Yue Wang ◽  
Yi-Jian Jiang
Keyword(s):  
Dielectric Properties ◽  
Composition Dependence ◽  
Polycrystalline Ceramics

Sintering and dielectric properties of (Ta2O5)1−x (TiO2) x polycrystalline ceramics

2007 ◽  
Vol 21 (1-4) ◽  
pp. 577-580 ◽  
Author(s):  
Yue Wang ◽  
Xue-wen Zhu ◽  
Yi-jian Jiang
Keyword(s):  
Dielectric Properties ◽  
Polycrystalline Ceramics

Microwave dielectric properties of MO–La2O3–TiO2 (M = Ca, Sr, Ba) ceramics

2002 ◽  
Vol 17 (12) ◽  
pp. 3084-3089 ◽  
Author(s):  
Isuhak Naseemabeevi Jawahar ◽  
Narayana Iyer Santha ◽  
Mailadil Thomas Sebastian ◽  
Pezholil Mohanan
Keyword(s):  
Dielectric Properties ◽  
Single Phase ◽  
Microwave Dielectric Properties ◽  
Quality Factors ◽  
X Ray Diffraction ◽  
Microwave Dielectric ◽  
Narrow Bandwidth ◽  
Polycrystalline Ceramics ◽  
State Ceramic ◽  
High Dielectric

Single-phase polycrystalline ceramics in the MO–La2O3–TiO2 (M = Ca, Sr, Ba) system, such as cation-deficient hexagonal perovskites CaLa4Ti4O15, SrLa4Ti4O15, BaLa4Ti4O15, and Ca2La4Ti5O18 and the orthorhombic phases CaLa4Ti5O17 and CaLa8Ti9O31, were prepared through the solid-state ceramic route. The phases and structure of the ceramics were analyzed through x-ray diffraction and scanning electron microscopy. The microwave dielectric properties of the ceramics were studied using a network analyzer. The investigated ceramics show high εr in the range 42 to 54, high quality factors with Q ×f in the range 16,222 to 50,215 GHz, and low Tf in the range –25 to +6 ppm / °C. These high dielectric constant materials with high Q × f up to 50,215 GHz are suitable for applications where narrow bandwidth and extremely low insertion loss is necessary, especially at frequencies around 1.9 GHz.

Composition Dependence of Microstructure and Dielectric Properties in Alkoxy-Derived Ba(Ti,Zr)O3Thin Films

2006 ◽  
Vol 45 (1A) ◽  
pp. 155-159 ◽  
Author(s):  
Kiyotaka Tanaka ◽  
Kazuyuki Suzuki ◽  
Kaori Nishizawa ◽  
Takeshi Miki ◽  
Kazumi Kato
Keyword(s):  
Dielectric Properties ◽  
Composition Dependence

scholarly journals Dielectric properties of amorphous Zr–Al–O and Zr-Si-O thin films

2015 ◽  
Vol 05 (01) ◽  
pp. 1550010 ◽  
Author(s):  
T. A. Naoi ◽  
Hanjong Paik ◽  
M. L. Green ◽  
R. B. van Dover
Keyword(s):  
Dielectric Properties ◽  
Composition Dependence ◽  
Abrupt Change ◽  
Low Frequency ◽  
Index Of Refraction ◽  
Systematic Deviation ◽  
Chemical Systems ◽  
Oxygen Coordination ◽  
Local Oxygen ◽  
Deposited Films

We have systematically studied the composition dependence of the dielectric properties of Zr 1-x Al x O 2-x/2 and Zr 1-x Si x O 2. An essentially linear variation of the static dielectric constant, εs, was observed as a function of composition, x, for compositions rich in the p-block element, i.e., x > 0.4, for both chemical systems. However an abrupt change in εs is found near x ≈ 0.35, associated with the onset of crystallinity in as-deposited films. Breakdown fields do not show a comparable composition dependence. Measurements of the index of refraction at optical frequencies, combined with a simple Clausius–Mossotti interpretation, indicates that low-frequency (ionic) contributions to the polarizability exhibit systematic deviation with respect to values linearly interpolated from the endmembers. These trends are not consistently affected by the presence of crystalline order, but are related to changes associated with heterogeneous local oxygen coordination and bonding.

High-Temperature Dielectric Properties of Polycrystalline Ceramics

1988 ◽  
Vol 124 ◽  
Author(s):  
W. W. Ho
Keyword(s):  
High Temperature ◽  
Dielectric Properties ◽  
Volume Expansion ◽  
Room Temperature ◽  
Experimental Methods ◽  
Dielectric Constants ◽  
Amorphous Phases ◽  
Temperature Loss ◽  
Polycrystalline Ceramics ◽  
Impurity Doping

ABSTRACTExperimental methods for determining the high-temperature millimeter-wave dielectric properties of solids are described and the data obtained on a wide variety of polycrystalline ceramics are reviewed. In general, the observed increase in dielectric constants with temperature can be modeled with a macroscopic dielectric virial expansion and shown to be primarily caused by an increase in polarizability due to volume expansion. The room-temperature loss tangents in low-absorption ceramics are probably caused by impurity doping of the primary and secondary crystalline phases at grain junctions and along grain boundaries. The rapid increase in loss tangent at high temperatures commonly observed in polycrystalline ceramics is associated with softening of intergranular amorphous phases resulting in an increase in localized electrical conductivity.

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