X-ray Diffraction, Dielectric, and Raman Spectroscopy Studies of SrTiO3-Based Microwave Ceramics

Qu, Jingjing; Liu, Fei; Wei, Xing; Yuan, Changlai; Liu, Xinyu; Chen, Guohua; Feng, Qin

doi:10.1007/s11664-015-4183-9

Cited by 12 publications

(4 citation statements)

References 25 publications

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“…Figure shows Raman spectra of four samples in the frequency range 150‐850 cm −1 . The Raman spectra of SrTiO 3 are dominated by two major scattering bands centered at 372 cm −1 and 612 cm −1 in line with the literatures . For Ca 0.7 Sm 0.2 TiO 3 ceramic, the bands below 400 cm −1 are assigned as rotations of the oxygen cage, the two bands at 472 and 516 cm −1 originate from Ti–O torsional modes, and the band at 654 cm −1 belongs to Ti–O stretching modes.…”

Section: Resultssupporting

confidence: 87%

Complex impedance spectroscopy of perovskite microwave dielectric ceramics with high dielectric constant

et al. 2018

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The AC impedance of SrTiO3, Ca0.9Sr0.1TiO3, Ca0.7Sm0.2TiO3, and Ca0.7Sm0.3Ti0.7Al0.3O3 microwave dielectric ceramics with perovskite structures has been analyzed. The impedance spectroscopy results reveal the electrical properties of this series of samples vary significantly with the ceramic microstructure and electrical homogeneity. The εr values of grains for SrTiO3 and Ca0.9Sr0.1TiO3 ceramics are 193.8 and 138.1, respectively, confirming that dielectric response of the high‐εr microwave ceramics is contributed to the grains, at microwave frequencies. Impedance spectroscopy of Ca0.7Sm0.2TiO3 ceramic illustrates that electrical heterogeneous microstructures include interior grains and grain shells. The secondary phase existing in Ca0.7Sm0.2TiO3 ceramic causes deviation in bulk permittivity, resulting in a higher εr ~ 148 of grains than εr ~ 112 of bulk permittivity, measured at microwave frequencies. Grain and grain‐boundary impedance of Ca0.7Sm0.3Ti0.7Al0.3O3 ceramic cannot be separated completely. The permittivities of grains and grain boundaries in Ca0.7Sm0.3Ti0.7Al0.3O3 ceramic are εg ~ 17.8 and εgb ~ 20.8, and the combination of them is close to εr ~ 40 at microwave frequencies. The LogI−LogU curves of the ceramic system indicate that the conducting mechanism of grains and grain boundaries follows ohmic behavior.

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Section: Resultssupporting

confidence: 87%

Complex impedance spectroscopy of perovskite microwave dielectric ceramics with high dielectric constant

et al. 2018

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“…4,5 Therefore, the dielectric materials with high e r and quality factors (Qf) have been given much attention. Recently, high dielectric constant SrTiO 3 ceramics have been explored, 6,7 however, the relatively low Qf (~3000) severely limits their practical application. Related studies show that oxygen loss occurs in most titanate-based materials under high sintering temperature, resulting in partially reduction in Ti 4+ to Ti 3+ and increase in dielectric loss.…”

Section: Introductionmentioning

confidence: 99%

High dielectric constant and high‐Q in microwave ceramics of SrTiO₃ co‐doped with aluminum and niobium

Chen¹,

Li²,

Yu³

et al. 2018

J Am Ceram Soc

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Al/Nb co-doped SrTiO 3 microwave ceramics with the composition of SrTi 1-x (Al 0.5 Nb 0.5 ) x O 3 (x = 0.03, 0.05, 0.1, and 0.15) have been synthesized via a standard solid-state reaction method. The substitution of (Al 0.5 Nb 0.5 ) 4+ in B-site inhibits the reduction in Ti 4+ ions and the growth of grain size, then the transport of mobile charge carriers is limited, and thus the Q value is improved. For the SrTi 0.9 (Al 0.5 Nb 0.5 ) 0.1 O 3 ceramics, in addition to their high dielectric constant (e r 185), they exhibit correspondingly a high Qf value (~9077 GHz) at 2.9 GHz, making the microwave ceramics suitable for myriad device miniaturization and high-performance wireless communication. K E Y W O R D Sdielectric materials/properties, electroceramics, microwaves

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“…However, it is worth noting that a new peak R14 appears after doping with Ti 4+ -ions when x ≥ 0.1, and the intensity of R14 vibration modes gradually increases; the frequency band here should also be marked as caused by O-Ti-O bending vibration [30]. Meanwhile, the intensity of the R13 vibration modes also gradually increases with the increase in TiO2 content, and the Raman band at 500-650 cm −1 can be attributed to the Ti-O stretching vibration of the TiO6 octahedron [31]. Both these two Raman modes belong to the Sr2TiO4 phase.…”

Section: Resultsmentioning

confidence: 88%

Phase Structures and Dielectric Properties of (n + 1)SrO − nCeO2 (n = 2) Microwave Ceramic Systems with TiO2 Addition

Liu

et al. 2023

Crystals

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Ti4+-ion-doped (n + 1)SrO − nCeO2 (n = 2) ceramic systems were prepared with the conventional solid-state reaction method, and the effects of the phase structures and compositions, sintering behaviors, microstructures and microwave dielectric properties of these ceramic systems were investigated in detail as a function of TiO2 content. The analytical results of the XRD patterns show that the pure (n + 1)SrO − nCeO2 (n = 2) system is a composite-phase ceramic system with coexisting SrCeO3 and Sr2CeO4 phases (represented as a SrCeO3 + Sr2CeO4 system), which belong to the orthogonal structures of the Pmcn (62) and Pbam (55) space groups, respectively. For the xTiO2-(1 − x) (SrCeO3 + Sr2CeO4) (x = 0.1–0.4) ceramic samples, the secondary phase Sr2TiO4 can also be detected within the range of the investigated components. Meanwhile, the Raman spectroscopy, SEM-EDS, and HRTEM (SAED) analysis results also verified the correctness and consistency of the phase structures and compositions for all the given specimens. In addition, complex impedance spectroscopy was used to detect the conductive behavior of these compound ceramic systems, and the calculation results show that the appropriate addition of Ti4+-ions can make the SrCeO3 + Sr2CeO4 system have better thermal stability. The composition of x = 0.2 multiphase structural ceramic sample sintered at 1330 °C for 4 h has a near zero τf value of ~−4.6 ppm/°C, a moderate εr of ~40.3 and a higher Q × f~44,020 GHz (at 6.56 GHz). The relatively superior-performing ceramics developed in this work are expected to provide a promising microwave dielectric material for communication components.

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X-ray Diffraction, Dielectric, and Raman Spectroscopy Studies of SrTiO3-Based Microwave Ceramics

Cited by 12 publications

References 25 publications

Complex impedance spectroscopy of perovskite microwave dielectric ceramics with high dielectric constant

Complex impedance spectroscopy of perovskite microwave dielectric ceramics with high dielectric constant

High dielectric constant and high‐Q in microwave ceramics of SrTiO₃ co‐doped with aluminum and niobium

Phase Structures and Dielectric Properties of (n + 1)SrO − nCeO2 (n = 2) Microwave Ceramic Systems with TiO2 Addition

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X-ray Diffraction, Dielectric, and Raman Spectroscopy Studies of SrTiO3-Based Microwave Ceramics

Cited by 12 publications

References 25 publications

Complex impedance spectroscopy of perovskite microwave dielectric ceramics with high dielectric constant

Complex impedance spectroscopy of perovskite microwave dielectric ceramics with high dielectric constant

High dielectric constant and high‐Q in microwave ceramics of SrTiO3 co‐doped with aluminum and niobium

Phase Structures and Dielectric Properties of (n + 1)SrO − nCeO2 (n = 2) Microwave Ceramic Systems with TiO2 Addition

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High dielectric constant and high‐Q in microwave ceramics of SrTiO₃ co‐doped with aluminum and niobium