The relationship between the bond ionicity, lattice energy, bond energy and microwave dielectric properties of LaNbO4 ceramics

Xiao, Mi; Wei, Yanshuang; Gu, Qingqing; Zhang, Ping

doi:10.1007/s10854-018-9038-8

Cited by 21 publications

(13 citation statements)

References 22 publications

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“…As for the Q×f values, the determinants may become more complicated: in addition to the secondary phase and porosity that have been discussed, the defects and stability of crystal lattice may also play an important role [6,42]. Bond length, bond valence and bond energy are important factors that re ect the stability of crystal lattice, and have been used to explore the relationship between the structure and properties of microwave dielectric properties [43][44][45]. However, according to the results of Rietveld re nement, the variation of the average bond length of the ceramics related to z value is less than 0.01 Å, which is roughly equivalent to the uncertainty of Rietveld re nement method (~ 0.006 Å).…”

Section: Resultsmentioning

confidence: 99%

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

Guo

Luo

et al. 2021

Preprint

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Low-loss tungsten-bronze microwave dielectric ceramics are a kind of dielectric materials with potential application value for miniaturized dielectric filters and antennas in 5G communication technology. In this work, a novel Al/Nd co-doping method of Ba4Nd9.33Ti18O54 (BNT) ceramics with a chamical formula of Ba4Nd9.33+z/3Ti18-zAlzO54 (BNT-AN, 0 ≤ z ≤ 2) was proposed to improve the dielectric properties through structural and defect modulation. Together with Al-doped ceramics (Ba4Nd9.33Ti18-zAl4z/3O54, BNT-A, 0 ≤ z ≤ 2) for comparison, the ceramics were prepared by solid state method. It is found that Al/Nd co-doping method has a significant effect on improving the dielectric properties compared with Al doping. As the doping amount z increased, the relative dielectric constant (εr) and the temperature coefficient of resonant frequency (τf) of the ceramics decreased, and the Q×f values of the ceramics obviously increased when z ≤ 1.5. 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. Raman spectroscopy and thermally stimulated depolarization current (TSDC) technique were firstly combined to analyze the structure and defects in the dielectric ceramics. It is shown that the improvement on Q×f values were origined from the decrease in the strength of the A-site cation vibration and the concentration of oxygen vacancies (Vö), demonstrating the effect and mechanism underlying for structural and defect modulation on the performance improvement of microwave dielectric ceramics.

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Section: Resultsmentioning

confidence: 99%

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

Guo

Luo

et al. 2021

Preprint

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“…Intrinsic losses were mainly caused by lattice vibration modes, while the extrinsic losses were dominated by second phases, oxygen vacancies, grain sizes and densification or porosity. [17][18][19] In this work, according to the analysis of XRD results, the crystal phase of samples were basically same with various sintering temperature, therefore, the intrinsic factor on the Q 9 f values was not under consideration. In other words, the Q 9 f values were mainly affected by the extrinsic factor in this article.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and microwave dielectric properties of new high quality Mg₂NdNbO₆ ceramics

et al. 2017

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New high‐quality microwave dielectric ceramics Mg2NdNbO6 were prepared by conventional solid‐state sintering method. The phases, micro‐structures and microwave dielectric properties of Mg2NdNbO6 ceramics were investigated at sintering temperature in the range of 1275°C‐1400°C. The X‐ray diffraction patterns showed that the peaks of the compounds were attributed to two phases, including the main crystalline phase of NdNbO4 that was indexed as the monoclinic phase and MgO as the second phase. Well‐developed microstructures of Mg2NdNbO6 ceramics can be achieved, and the grain size reached the maximum value (1.63 μm) at 1375°C. As the sintering temperature increased, the dielectric constant, temperature coefficient of resonant frequency and apparent density remained almost unchanged, however, the significant change in the quality factor was observed. At 1375°C, Mg2NdNbO6 ceramics possessed excellent microwave dielectric properties: εr = 16.22, Q × f = 116 000 GHz and τf = −30.96 ppm/°C.

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“…For sintering behavior, the sintering temperature can be reduced to 1150 of ℃ MgNb 2 O 6 by sol-gel method [142]. Doped ceramics of (Zn 1-x Ni x )Ta 2 O 6 [143], Zn(Ta 1-x Nb x ) 2 O 6 [144], Zn(Ta 1-x Sb x ) 2 O 6 [145], and composite ceramics composed of ZnO-Nb 2 O 5 -1.75TiO 2 -5 mol% MgO,…”

Section: Rutile-trirutile/ixiolite/wolframite-columbite Type Ceramicsmentioning

confidence: 99%

The latest process and challenges of microwave dielectric ceramics based on pseudo phase diagrams

et al. 2021

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The explosive process of 5G communication evokes the urgent demand of miniaturized and integrated dielectric ceramics filter. It is a pressing need to advance the development of dielectric ceramics utilization of emerging technology to design new materials and understand the polarization mechanism. This review provides the summary of the study of microwave dielectric ceramics (MWDCs) sintered higher than 1000 from 2010 up to now, °C with the purpose of taking a broad and historical view of these ceramics and illustrating research directions. To date, researchers endeavor to explain the structure-property relationship of ceramics with multitude of approaches and design a new formula or strategy to obtain excellent microwave dielectric properties. There are variety of factors that impact the permittivity, dielectric loss, and temperature stability of dielectric materials, covering intrinsic and extrinsic factors. Many of these factors are often intertwined, which can complicate new dielectric material discovery and the mechanism investigation. Because of the various ceramics systems, pseudo phase diagram was used to classify the dielectric materials based on the composition. In this review, the ceramics were firstly divided into ternary systems, and then brief description of the experimental probes and complementary theoretical methods that have been used to discern the intrinsic polarization mechanisms and the origin of intrinsic loss was mentioned. Finally, some perspectives on the future outlook for high-temperature MWDCs were offered based on the synthesis method, characterization techniques, and significant theory developments.

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The relationship between the bond ionicity, lattice energy, bond energy and microwave dielectric properties of LaNbO4 ceramics

Cited by 21 publications

References 22 publications

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

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

Synthesis and microwave dielectric properties of new high quality Mg₂NdNbO₆ ceramics

The latest process and challenges of microwave dielectric ceramics based on pseudo phase diagrams

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The relationship between the bond ionicity, lattice energy, bond energy and microwave dielectric properties of LaNbO4 ceramics

Cited by 21 publications

References 22 publications

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

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

Synthesis and microwave dielectric properties of new high quality Mg2NdNbO6 ceramics

The latest process and challenges of microwave dielectric ceramics based on pseudo phase diagrams

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Synthesis and microwave dielectric properties of new high quality Mg₂NdNbO₆ ceramics