Characterization of Co0.5(Ti1−xZrx)0.5NbO4 microwave dielectric ceramics based on structural refinement

Li, Yaoyao; Lu, Xiaochi; Zhang, Yan; Zou, Yanyan; Wang, Lixi; Zhu, Hongtao; Fu, Zhenxiao; Zhang, Qitu

doi:10.1016/j.ceramint.2017.06.025

Cited by 34 publications

(4 citation statements)

References 43 publications

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“…60) space group occurs in A 0.5 Ti 0.5 NbO 4 (A = Zn, Mg), and the dielectric properties of ε r = 33–37, Qf = 20000–40000 GHz, and τ f = −75 to −19 ppm/°C were reported. , A rutile structure with the P 4 2 / mnm (No. 136) space group is confirmed in A 0.5 Ti 0.5 NbO 4 (A = Co, Ni), which has ε r of about 65, Qf of 13000 GHz, and τ f of 180 ppm/°C …”

Section: Introductionmentioning

confidence: 91%

“…136) space group is confirmed in A 0.5 Ti 0.5 NbO 4 (A = Co, Ni), which has ε r of about 65, Qf of 13000 GHz, and τ f of 180 ppm/°C. 13 Considering that Nb 5+ and Ta 5+ ions have the similar ionic radii (0.64 Å) 14 at the same coordination number (CN = 6) and close electronegativity, it drives us to wonder if the A 0.5 B 0.5 TaO 4 ceramics could be prepared. Recent studies have shown the possibility of the preparation of CoZrTa 2 O 8 MWDCs, 15 which shares the same monoclinic wolframite structure with CoZrNb 2 O 8 .…”

Section: Introductionmentioning

confidence: 99%

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Crystal Chemistry, Raman Spectra, and Bond Characteristics of Trirutile-Type Co_0.5Ti_0.5TaO₄ Microwave Dielectric Ceramics

Yang¹,

Zhang²,

Chen³

et al. 2018

Inorg. Chem.

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A novel trirutile-type Co0.5Ti0.5TaO4 ceramic was reported here for the first time. The correlations between the sintering behavior, crystal structure, chemical bond, and dielectric properties were investigated. Pure Co0.5Ti0.5TaO4 ceramic was synthesized in the temperature range of 1000–1100 °C. A trirutile structure and refined parameters of a = b = 4.71163 Å, c = 9.13586 Å, and V cell = 202.811 Å3 could be obtained (1075 °C). According to the P–V–L chemical bond theory, majority contributions to the dielectric constant originated from Ta–O bonds, owing to its largest bond ionicity and bond susceptibility values. The experimental dielectric constant is close to the theoretical values calculated via the P–V–L chemical bond theory and Clausius–Mossotti relationship. The Ta–O bonds that present the largest lattice energy are also the main factors influencing the intrinsic loss. The τf value is consistent with the oxygen distortions of the octahedron. More importantly, variations of the densification, average grain size, and grain boundary are crucial factors for development of the microwave dielectric properties. The Raman spectra and group theory were analyzed together, and the results indicated that the A1g mode at 687.45 cm–1, which reflects the stretching vibrations of the O anions, dominates the Raman vibrations. Typical microwave dielectric properties of Co0.5Ti0.5TaO4 ceramics were obtained when sintered at 1075 °C: εr = 40.69, Qf = 17291 GHz, and τf = 114.54 ppm/°C.

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Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Crystal Chemistry, Raman Spectra, and Bond Characteristics of Trirutile-Type Co_0.5Ti_0.5TaO₄ Microwave Dielectric Ceramics

Yang¹,

Zhang²,

Chen³

et al. 2018

Inorg. Chem.

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“…The Nb‐site bond valence and NbO 6 octahedral distortions were calculated using Rietveld refinement. The NbO 6 octahedral distortion was calculated using Equation

δ = \frac{1}{6} \sum {()(, \frac{R_{i} - \bar{R}}{\bar{R}})}^{2}

where

\bar{R}

and R i are the average and individual bond lengths of Nb‐O bonds, respectively.…”

Section: Resultsmentioning

confidence: 99%

Crystal structure and enhanced microwave dielectric properties of Ta⁵⁺ substituted Li₃Mg₂NbO₆ ceramics

et al. 2019

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Composition and structure play dominant roles in realizing the microwave dielectric properties that are necessary for the ever‐increasing demands of the Internet of Things and related communication technologies. In the present study, the substitution of Ta5+ in Li3Mg2Nb1−xTaxO6 ceramics and its effect on the structural characteristics and microwave dielectric performances is systematically studied. All the substituted compositions were determined to be pure phase orthorhombic Li3Mg2NbO6 structure of space group Fddd. Furthermore, a NbO6 octahedral distortion, Nb‐O bond valence, packing fraction and polarizability were calculated to explore the structure‐property‐performance paradigm in the context of microwave dielectric performance. Scanning electron microscopy revealed homogeneous microstructures, with the introduction of Ta5+ promoting grain growth. Raman spectra indicated that the variation of the band (blue shift and red shift) at 771 cm−1 was highly correlated with the variation in unit cell volume. The polarizability significantly impacted ɛr values. The Q × f values were strongly influenced by the packing fraction and grain size. The changes in the NbO6 octahedral distortion and Nb–O bond valence impacted the τf values. The Li3Mg2Nb0.98Ta0.02O6 composition displayed the most dramatic improvements in microwave dielectric properties: εr = 15.58, Q × f = 113 000 GHz and τf = −4.5 ppm/°C, providing a potential candidate for next generation microwave and millimeter‐wave applications.

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“…Introduction of CoNb 2 O 6 and Zn 1.01 Nb 2 O 6 into CoTiNb 2 O 8 rendered the Q×f increasing considerably due to the enhanced densification and obtained the τ f values of 0.5 and 0 ppm/ , respectively [114,115]. ℃ Zhang et al [116] and Li et al [117] reported that τ f value would shift from positive to negative after Zr substitution in CoTi 1-x Zr x Nb 2 O 8 , where the τ f value was correlated with oxygen octahedral distortion and B-site bond valence. Superlattice diffraction peak which is relevant with cation ordering was observed in Co 0.5 Ti 0.5 Nb 1-x Sb x O 4 ceramics, contributing to the augment of Q×f value [118].…”

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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Characterization of Co0.5(Ti1−xZrx)0.5NbO4 microwave dielectric ceramics based on structural refinement

Cited by 34 publications

References 43 publications

Crystal Chemistry, Raman Spectra, and Bond Characteristics of Trirutile-Type Co_0.5Ti_0.5TaO₄ Microwave Dielectric Ceramics

Crystal Chemistry, Raman Spectra, and Bond Characteristics of Trirutile-Type Co_0.5Ti_0.5TaO₄ Microwave Dielectric Ceramics

Crystal structure and enhanced microwave dielectric properties of Ta⁵⁺ substituted Li₃Mg₂NbO₆ ceramics

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

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Characterization of Co0.5(Ti1−xZrx)0.5NbO4 microwave dielectric ceramics based on structural refinement

Cited by 34 publications

References 43 publications

Crystal Chemistry, Raman Spectra, and Bond Characteristics of Trirutile-Type Co0.5Ti0.5TaO4 Microwave Dielectric Ceramics

Crystal Chemistry, Raman Spectra, and Bond Characteristics of Trirutile-Type Co0.5Ti0.5TaO4 Microwave Dielectric Ceramics

Crystal structure and enhanced microwave dielectric properties of Ta5+ substituted Li3Mg2NbO6 ceramics

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

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Crystal Chemistry, Raman Spectra, and Bond Characteristics of Trirutile-Type Co_0.5Ti_0.5TaO₄ Microwave Dielectric Ceramics

Crystal Chemistry, Raman Spectra, and Bond Characteristics of Trirutile-Type Co_0.5Ti_0.5TaO₄ Microwave Dielectric Ceramics

Crystal structure and enhanced microwave dielectric properties of Ta⁵⁺ substituted Li₃Mg₂NbO₆ ceramics