Effects of Zn2+ substitution on the crystal structure, Raman spectra, bond energy and microwave dielectric properties of Li2MgTiO4 ceramics

Wang, P.; Wang, Y.R.; Bi, J.X.; Wu, Haitao

doi:10.1016/j.jallcom.2017.05.323

Cited by 29 publications

(4 citation statements)

References 23 publications

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“…8, where the ordered-disordered range was summarized from Zhang et al [246,247]. Simultaneously, Gu et al [248] [250], and a near zero τ f (-4.03 ppm/ ) was ℃ obtained for 0.1 mol Zn substitution for Mg [251]. [253].…”

Section: Rock-salt Structurementioning

confidence: 93%

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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Section: Rock-salt Structurementioning

confidence: 93%

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

et al. 2021

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“…It is well known that the activities of vibration modes are affected by the local and long ranges symmetry of materials. According to Wang et al [47], as the ceramics become more disordered due to the variation of local symmetry, some inactive Raman modes will be activated. In fact, some degrees of octahedral disorder usually exist in the Li2ZnTi3O8 ceramics.…”

Section: Raman Spectroscopic Analysismentioning

confidence: 99%

Influences of substituting of (Ni_1/3Nb_2/3)⁴⁺for Ti⁴⁺on the phase compositions, microstructures, and dielectric properties of Li₂Zn[Ti_1−x(Ni_1/3Nb_2/3)_x]₃O₈(0 ≤x≤ 0.3) microwave ceramics

Li¹,

Wang²,

Guo³

et al. 2023

Journal of Advanced Ceramics

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Complex ions substitution is gaining more attention as an appealing method of modifying the structure and performance of microwave ceramics. In this work, Li2Zn[Ti1-x(Ni1/3Nb2/3)x]3O8 (LZTNNx, 0 ≤ x ≤ 0.3) ceramics were designed based on complex ions substitution strategy, following the substitution rule of radius and valence to investigate the 2 / 41 relationships between phase composition (containing oxygen vacancies and Ti 3+ ions), microstructure, and microwave dielectric characteristics of LZTNNx ceramics. The samples maintained a single Li2ZnTi3O8 solid solution phase as x ≤ 0.2 whereas the x = 0.3 sample produced a secondary phase with LiNbO3 structure. The appropriate amount of (Ni1/3Nb2/3) 4+ substitution could slightly improve the densification of LZTNNx ceramics due to the formation of Li2ZnTi3O8 solid solution accompanied by a decrease in average grain size. The presence of a new A1g Raman active band at about 848 cm -1 indicated that the local symmetry changed, affecting the atomic interactions of LZTNNx ceramics. The variation in dielectric constant (εr) was closely related to molar volume ionic polarizability, and the temperature coefficient of resonant frequency (τf) was related to the bond valence of Ti. The increase in density, the absences of Ti 3+ ions and oxygen vacancies, and the reduction in damping behavior were responsible for decreased dielectric loss. The LZTNN0.2 ceramic sintered at 1120 o C exhibited favorable microwave dielectric properties: εr = 22.13, quality factor (Q×f) = 97350 GHz, and τf = −18.6 ppm/ o C, which might be a promising candidate for wireless communication applications in highly selective electronics.

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“…24,25 Dielectric properties of LMTO ceramics reported in recent years, as well as the dielectric properties following modification, are shown in Figure 1B. 23,[26][27][28][29][30][31][32][33][34][35] Overall, researchers have worked on improving preparation process or using ionic substitution to optimize dielectric properties. In recent years, it has been demonstrated that crystal structure and dielectric properties of dielectric materials are significantly impacted by measurable and controlled compositional changes.…”

Section: Introductionmentioning

confidence: 99%

“…At the same time, LMTO can significantly reduce the device's mass because its density (∼3.45 g/cm 3 ) is lower than that of commercial K20 MWDCs (0.95MgTiO 3 –0.05CaTiO 3 , 3.7 g/cm 3 ) 24,25 . Dielectric properties of LMTO ceramics reported in recent years, as well as the dielectric properties following modification, are shown in Figure 1B 23,26–35 . Overall, researchers have worked on improving preparation process or using ionic substitution to optimize dielectric properties.…”

Section: Introductionmentioning

confidence: 99%

Effect of excess lithium on the structure and microwave dielectric properties of LiMg_0.5Ti_0.5O₂ ceramics

et al. 2023

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Herein, Li1+xMg0.5Ti0.5O2 (0.000 ≤ x ≤ 0.075) ceramics with excess lithium were prepared by solid‐state reaction method to compensate for lithium volatilization, thus optimizing dielectric properties. The second phase Mg2TiO4 decreases with excess lithium content and eventually disappears at x = 0.05. Of these, Li1.0375Mg0.5Ti0.5O2 illustrates the best dielectric properties with εr = 16.58, Q × f = 120712 GHz (@9.18 GHz), and τf = −16.31 ppm/°C. From the point of view of non‐intrinsic factors, excess lithium at optimum ratios slightly facilitates the sintering of the ceramics, improves densification, and increases the grain size, resulting in improved dielectric properties. For intrinsic factors, a slight increase in bond ionicity results in a slight improvement in εr. First‐principles calculations demonstrate that suitable excess lithium increases electron cloud density in the internal space of Li/Mg/TiO6 octahedron and increases band gap, thus optimizing the dielectric properties. The same results were obtained from the perspective of lattice vibrations. The modified Li1.0375Mg0.5Ti0.5O2 ceramics offer great potential for future microwave communication technology.

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Effects of Zn2+ substitution on the crystal structure, Raman spectra, bond energy and microwave dielectric properties of Li2MgTiO4 ceramics

Cited by 29 publications

References 23 publications

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

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

Influences of substituting of (Ni_1/3Nb_2/3)⁴⁺for Ti⁴⁺on the phase compositions, microstructures, and dielectric properties of Li₂Zn[Ti_1−x(Ni_1/3Nb_2/3)_x]₃O₈(0 ≤x≤ 0.3) microwave ceramics

Effect of excess lithium on the structure and microwave dielectric properties of LiMg_0.5Ti_0.5O₂ ceramics

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Effects of Zn2+ substitution on the crystal structure, Raman spectra, bond energy and microwave dielectric properties of Li2MgTiO4 ceramics

Cited by 29 publications

References 23 publications

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

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

Influences of substituting of (Ni1/3Nb2/3)4+for Ti4+on the phase compositions, microstructures, and dielectric properties of Li2Zn[Ti1−x(Ni1/3Nb2/3)x]3O8(0 ≤x≤ 0.3) microwave ceramics

Effect of excess lithium on the structure and microwave dielectric properties of LiMg0.5Ti0.5O2 ceramics

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Influences of substituting of (Ni_1/3Nb_2/3)⁴⁺for Ti⁴⁺on the phase compositions, microstructures, and dielectric properties of Li₂Zn[Ti_1−x(Ni_1/3Nb_2/3)_x]₃O₈(0 ≤x≤ 0.3) microwave ceramics

Effect of excess lithium on the structure and microwave dielectric properties of LiMg_0.5Ti_0.5O₂ ceramics