JOURNAL OF ALLOYS AND COMPOUNDS
·
2013
·
IF 2.39
Songping Wu,Juanjuan Xue,Rui Wang,Jianhui Li
Spinel MgGa 2 O 4 ceramic materials were synthesized by solid-state method. MgGa 2 O 4 powders were investigated with X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectrum, Raman spectrum, X-ray photoelectron spectrum (XPS), and high resolution transmission electron microscopy (HRTEM). The spinel-structured MgGa 2 O 4 ceramics sintered at 1410 °C exhibited excellent microwave dielectric properties: a dielectric constant ( ɛ r ) of 9.54, a quality factor ( Q × f ) of 117,000 GHz (at 14.7 GHz frequency) and a temperature coefficient of resonant frequency ( τ f ) of −4.0 ppm/°C. MgGa 2 O 4 ceramics have a wide sintering temperature region (∼150 °C) and nearly zero τ f value. The large relative density, uniform microstructure and cation ordering resulted in high Q × f values. Crystal distortion from the oriented growth was advantageous to produce nearly zero τ f value. MgGa 2 O 4 ceramics are promising candidate materials for millimeter-wave devices.
研究领域:
材料科学
·
电子工程
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DOI
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2017
·Vol. 19
·期 8
·1-7
·
IF 2.02
Li Nannan,Liu Jian,Duan Xiulan,Yu Fapeng,Jiang Huaidong
This report discusses the preparation and microstructure of Co/Ni co-doped MgGa 2 O 4 nanoparticles. The nanoparticles with the size of 20–55 nm were synthesized by sol-gel method. The phase and crystallinity were confirmed by X-ray powder diffraction (XRD) pattern. The particle size was estimated according to XRD data and transmission electron microscopy. The electronic structure was studied using X-ray photoelectron spectroscopy (XPS). The XPS studies showed that Ga 3+ ions possess tetrahedral and octahedral sites of spinel structure and the inverse degree (two times of the fraction of tetrahedral Ga 3+ ions) has increased with the increase of the doping concentration of Co 2+ and Ni 2+ ions. For Co/Ni co-doped MgGa 2 O 4 , two broad absorption bands of 350~500 and 550~700 nm were observed in the absorption spectra. The broad band at 350~500 nm was assigned to the combination of the absorption of octahedral Co 2+ and Ni 2+ ions, whereas the absorption band at 550~700 nm is mainly due to tetrahedrally coordinated Co 2+ ions and octahedrally coordinated Ni 2+ ions.
研究领域:
材料科学
·
纳米技术
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DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2025
·
IF 6.2
Chenglong Wang,Luchao Ren,Zixin Zhang,Hui Peng,Cuncheng Li,Panpan Lyu,Qingyang Du,Mingwei Zhang
A dual-modification strategy combining (Li 0.5 Bi 0.5 ) 2+ substitution and BaCu(B 2 O 5 )/LiF atmosphere-assisted sintering was developed to reduce the sintering temperature of MgGa 2 O 4 ceramic. The strategy achieved a 360 °C reduction in sintering temperature (from 1610 to 1250 °C) while maintaining a high performance. The optimal sample (Li 0.5 Bi 0.5 ) x Mg 1- x Ga 2 O 4 ( x = 0.02) exhibited ε r = 9.41, Q × f = 127,159 GHz, and τ f = -39.6 ppm/°C. XRD and Rietveld refinement confirmed that the spinel structure was preserved upon doping, alongside a lattice expansion. Consistent with the enhanced Q × f , a Raman spectroscopy analysis revealed a narrowing of the T 2 g mode, indicating an improved structural ordering. Furthermore, τ f was improved to −39.6 ppm/°C, directly related to the induced lattice distortion and expansion. The enhanced performance was attributed to the synergistic effects of composite ion doping and atmosphere-assisted sintering. The former modified the intrinsic structure and polarization characteristics, while the latter facilitated the densification at lower temperatures.
研究领域:
材料科学
·
陶瓷工程
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Yuxin Xiao,Aihu Feng,Junge Chen,Qianying Cao,Le Mi,Yang Yu,Yanfeng Gao,Yun Yu
In this study, the viability of MgGa 2 O 4 as a pigment for thermal control coatings is discussed. Notably, the MgGa 2 O 4 based coating exhibited excellent initial optical properties and irradiation stability. After irradiation with 40 keV proton at a dose of 1.4 × 10 14 P/cm 2 , the optical performance of the coating remained essentially unchanged, while the solar absorption of the coating is still maintained below 0.10 after irradiation with 40 keV electron at a dose of 1.6 × 10 16 e/cm 2 . Further, the mechanism of the optical changes induced by electron irradiation was elucidated through experimental and computational methods. In MgGa 2 O 4 lattice, two different types of oxygen vacancies and a transition process of them were found. This process was accompanied by the leakage of some oxygen atoms from the lattice, leading to an increased number of color centers and the change in optical properties. Despite the solar absorption raised after electron irradiation , the MgGa 2 O 4 based thermal control coating showed minimal change and low end-of-irradiation-life values, which suggests that they have excellent stability and promising applications.
研究领域:
材料科学
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航天工程
·
光学
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产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2023
·
IF 8.4
Xinyuan Lyu,Luchao Ren,Le Xin,Zhengxin Li,Xianxin Zhang,Zheng Luo,Pengchao Shao,Yuxiao Zhang,Panpan Lyu,Mingwei Zhang
Fabrication of low-temperature co-fired ceramic (LTCC) densified at a low sintering temperature (<900 °C) is energy saving and environmentally friendly. Here, an interesting attempt has been made to lower the sintering temperature of MgGa2O4 by adding CuMoO4 for LTCC application. The sintering temperature of MgGa2O4 was remarkably reduced from 1410 to 900 °C, which contributed to energy saving. Furthermore, a series of studies on microstructure, sintering behavior, lattice parameters, and microwave dielectric characteristic of the samples were carried out. The occurrence of ion substitution between MgGa2O4 and CuMoO4, which affected the sintering densification, ionic polarizability, and Mg–O bond length, made the composites present various sintering and dielectric properties. Moreover, the full width half maximum (FWHM) value of the T2g peak in Raman spectra and lattice distortion were also analyzed to reveal the intrinsic interaction between structure and dielectric properties. Finally, the 0.5MgGa2O4–0.5CuMoO4 ceramics sintered at 900 °C showed the best comprehensive performance, εr = 6.8, Q × f = 15,800 GHz, τf = −54.2 ppm/°C. These promising properties make the composite more suitable for practical application.
研究领域:
材料科学
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电子工程
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DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2024
·
IF 3.2
Xiu-Zhen Yang,Tian-Qi Zhao,Renagul Abdurahman,Shi-Ji Liu,Yao-Xing Han,Yue Zhang,Xue-Bo Yin,Jie Gao
Fluorescence intensity ratio (FIR) technique demonstrates significant potential for non-contact temperature sensing with rapid response time, while the design of FIR probes is particularly intriguing. Herein, we report Pr–Al co-doped MgGa 2 O 4 persistent luminescence nanoparticles (PLNPs), as MgAl 0.04 Ga 1.96 O 4 : 0.1 % Pr 3+ (MAGP), for ratiometric temperature sensing application. Pr 3+ ions function as the emission centers for dual-emission at 612 and 494 nm, while Al 3+ ions adjust the lattice environment around Pr 3+ ions to enhance the luminescence. Consequently, 274 nm excitation induces the emissions at 494 and 612 nm, as the transitions of Pr 3+ for 3 P 0 → 3 H 4 and 1 D 2 → 3 H 4 , respectively. The emission mechanism is substantiated by density functional theory calculations, regarding the electronic transitions of Pr 3+ . Ratiometric temperature sensing is achieved over the temperature range of 303–573 K with the thermally non-coupled mechanism of the 3 P 0 / 1 D 2 energy levels by FIR at 612 and 494 nm, respectively. The maximum relative sensitivity was 0.91 %. The mechanism is corroborated as the non-thermally coupled energy levels through intervalence charge transfer. Thus, the reversible and sensitive response was illustrated for temperature measurement and the non-thermally coupled mechanism is efficient for the design of ratiometric temperature sensors.
研究领域:
材料科学
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光学工程
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Pengfei Wei,Cen Qian,Luchao Ren
This study demonstrates the successful synthesis of (1- x )MgGa 2 O 4 - x LiF ( x = 0.1–0.4, mass fraction) ceramics via solid-state reaction, achieving a significant reduction in sintering temperature from 1410 to 850 °C. The XRD and Raman testing results showed the formation of a new phase of LiGaO 2 , which affected the dielectric properties. Variations in the sintering density and ionic polarizability cause changes in the permittivity. In addition, the packing fraction analysis of MgGa 2 O 4 , which influences the crystal structure stability, elucidates the intrinsic mechanisms affecting the dielectric loss. The composite effect makes the τ f value of the ceramic shift toward the negative value, owing to the large negative frequency temperature coefficient of LiF. Finally, (1- x )MgGa 2 O 4 - x LiF ( x = 0.3) sintered at 850 °C possesses the superior dielectric properties: ε r = 9.45, Q × f = 32,790 GHz, τ f = −28.5 ppm/°C (at 14 GHz). In addition, (1- x )MgGa 2 O 4 - x LiF ( x = 0.3) ceramics exhibit good cofiring compatibility with Ag electrodes promoting the ceramic to be a suitable candidate for LTCC applications.
研究领域:
材料科学
·
电子工程
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高影响因子
JOURNAL OF ELECTRONIC MATERIALS
·
2024
·Vol. 53
·期 5
·2240-2249
·
IF 2.2
Shi Zitao,Li Shasha,Zheng Zeyu,Feng Xiaodong,Fang Zixuan,Yang Jun,Tang Bin
The rapidly developing field of wireless communication technology requires advanced microwave dielectric ceramic materials. Here, spinel-structured MgGa 2 O 4 and ZnGa 2 O 4 ceramics were prepared using a reaction sintering method. The effect of sintering temperature was investigated with respect to the crystal structure, microstructure, and microwave dielectric properties of MgGa 2 O 4 and ZnGa 2 O 4 ceramics. Rietveld refinement analysis and quality factor ( Q × f ) values suggested that the occupancy sites and percentage of cations in MgGa 2 O 4 would affect the microwave dielectric properties. Microstructure analysis indicated that abnormal grain growth at higher sintering temperatures would degrade the microwave dielectric properties of ZnGa 2 O 4 ceramics. MgGa 2 O 4 ceramics sintered at 1610°C exhibited promising microwave dielectric properties, i.e., ε r = 9.4, Q × f = 167,500 GHz, and τ f = −63 ppm/°C, while ZnGa 2 O 4 ceramics sintered at 1550°C possessed a higher ε r and a lower Q × f value of 10.5 and 126,900 GHz, respectively, and τ f = −60 ppm/°C. The τ f values of MgGa 2 O 4 and ZnGa 2 O 4 ceramics were tuned to near-zero levels by adding 8 mol.% CaTiO 3 . These results indicate that MgGa 2 O 4 and ZnGa 2 O 4 ceramics produced by reaction sintering show promise for applications in the field of 5G communication.
研究领域:
材料科学
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电子工程
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Peng Liu,Yuchi Zhang,Bohan Li,Le Han,Yan Xu
Anti-counterfeiting and encryption are key technologies for information transmission in modern society. Whereas, most optical materials reported only provide single luminous color and fixed response mode, which limits their safety in advanced anti-counterfeiting applications. In this work, we reported a Bi 3+ -assisted trap depth engineering strategy to achieve a dual-mode dynamic photoluminescence response of MgGa 2 O 4 : Bi 3+ with intriguing anti-counterfeiting and encryption performances. Upon the ultraviolet (UV) of 254 nm irradiation for 20 s, the color of MgGa 2 O 4 : x% Bi 3+ (x = 0, 1.0, 2.0, 3.0, 5.0) samples showed dynamic transformation from green or near-infrared to bluish-white emission. Combined with the dynamic photoluminescent (PL) behavior of MgGa 2 O 4 : 2.0% Bi 3+ , high-level dynamic anti-counterfeiting and encryption properties of MgGa 2 O 4 : Bi 3+ for tagging spies were investigated through powder filling followed by a masked screen printing method. On the other hand, the fluorescence intensity ratios (FIR) of I 430 nm /I 500 nm and I 430 nm /I 709 nm for MgGa 2 O 4 : 2.0% Bi 3+ showed excellent temperature-dependent quenching behaviors in the temperature range of 283 to 393 K, and the relative temperature sensitivities for FIR of I 430 nm /I 500 nm and I 430 nm /I 709 nm are 2.18% and 2.98% K −1 at 283 K, respectively. These results inspired more flexible designs to safeguard information security and develop novel high-efficiency optical temperature detectors.
研究领域:
材料科学
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光学
·
信息安全
·
温度传感
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Muxin Yu,Shuguang Zhang,Juxing Zhao,Shengping Wu,Hanling Wu,Yuxi Shao,Jiangquan Lv,Yonghua Wu,Weilong Zhang,Zhenhui Shen,Xiaoyan Li,Yunlong Yu
Materials integrating photochromism (PC), dynamic photoluminescence (PL) and persistent luminescence (PersL) exhibit significant potential for advanced anticounterfeiting and high-security information encryption through their multi-modal optical responses to external stimuli. Nevertheless, achieving the synergistic integration of these optical phenomena within a single material remains a significant challenge due to complex defect-related energy transfer processes. In this work, we developed a series of MgGa 2 O 4 :Sm 3+ (MGO:Sm) phosphors exhibiting reversible white-to-gray PC under 254 nm UV irradiation, accompanied by time-dependent dynamic PL color variations from dark red to light pink (or blue). Furthermore, the phosphors exhibit dynamic PersL, with emission color shifting from light pink (or blue) to red over time. Remarkably, Sm³ + doping not only enhances PC response but also enables color-tunable dynamic PL and PersL. Further analysis reveals that these multi-modal optical properties originate from complex interactions between traps, defect levels, and Sm³ + ions. The superior performance of MGO:Sm phosphors demonstrates their promising utility in advanced anticounterfeiting and encryption technologies.
研究领域:
材料科学
·
光学材料
·
光子学
·
安全技术
·
发光材料
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产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2024
·Vol. 12
·期 10
·3654-3661
·
IF 5.7
Yaowu Wang,Guocheng Pan,Jianfeng Wang,Yinyan Li,Zhenping Wu,Shiqing Xu,Gongxun Bai
Light-emitting diodes (LEDs) combined with near-infrared (NIR) phosphors are rapidly becoming important light sources for food safety, anti-counterfeiting and biological imaging due to non-destructive and non-toxic advantages. Single-phase materials with multi-mode luminescence under different stimuli are crucial for the development and applications of smart NIR phosphors. Here, we have developed multifunctional Cr3+ activated MgGa2O4 (MGO:Cr3+) phosphors with simultaneous photoluminescence and mechanoluminescence for NIR sensing. Under 470 nm excitation, the phosphors can produce emission bands from 650 to 850 nm. Meanwhile, the flexible devices based on phosphors can exhibit strong emissions in response to mechanical deformation, such as shock and friction. In addition, optical manometers based on luminescence from phosphors can achieve pressure sensing from 7 to 64 KPa. More intriguingly, we combined the MGO:Cr3+ phosphor with a blue LED chip to fabricate an NIR phosphor-converted LED for anti-counterfeiting and biological tissue penetration. Our results suggest that the multifunctional NIR phosphors with simultaneous photoluminescence and mechanoluminescence have potential applications in various sensing devices.
研究领域:
材料科学
·
光学传感
·
光子学
·
发光材料
·
智能传感器
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DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2026
·Vol. 47
·期 1
·118745
·
IF 6.3
Zhengxin Li,Hongcheng Yang,Hongyu Yang,Enzhu Li
To address the longstanding challenge of achieving cooperative optimization of thermal stability and mechanical properties in spinel ceramics, a high-entropy strategy was introduced into the MgGa 2 O 4 spinel system. Ceramics with varying configurational entropies were synthesized via a solid-state reaction at 1350–1450 °C. Results demonstrate that increasing configurational entropy significantly enhances lattice distortion and microstrain, successfully tuning the temperature coefficient of resonant frequency to near-zero (1.48 ± 1.55 ppm/°C). Simultaneously, elevated diffusion barriers trigger a sluggish diffusion effect, inhibiting grain growth. Furthermore, oxygen vacancies and chemical short-range order synergistically construct a three-dimensional dislocation-pinning network, substantially boosting flexural strength to 213.05 ± 7.03 MPa. Driven by the cocktail effect, this synergy achieves the simultaneous optimization of thermal stability and mechanical properties. This work reveals the underlying physical mechanisms of the four core high-entropy effects, providing a novel design strategy for next-generation microwave components with high flexural strength and excellent thermal stability.
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高影响因子
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