Influence of Yb and Si on the fabrication of Yb:YAG transparent ceramics using spherical Y2O3 powders

Yb:YAG (yttrium aluminum garnet) transparent ceramics were fabricated by the solid-state method using monodispersed spherical Y₂O₃ powders as well as commercial Al₂O₃ and Yb₂O₃ powders. Pure YAG phase was obtained at low temperature due to homogeneous mixing of powders. Under the same sintering conditions, the Yb:YAG ceramics with different doping contents of Yb³⁺ had similar morphologies and densification rates. After being sintered at 1700 °C in vacuum, the ceramic samples had high transparencies. The Yb:YAG ceramics doped with 0.5 wt% SiO₂ formed Y–Si–O liquid phase and nonstoichiometric point defects that enhanced sintering. Compared with Nd doping, Yb doping hardly affected the YAG grain growth, sintering densification or optical transmittance, probably because Yb³⁺ easily entered the YAG lattice and had a high segregation coefficient.     

Influence of Yb3+ doping on phase stability and thermophysical properties of (Y1-xYbx)3Al5O12 under high temperature

In this work, Yb³⁺ was selected to replace the Y³⁺ in yttrium aluminum garnet (YAG) in order to reduce its thermal conductivity under high temperature. A series of (Y_1-xYb_x)₃Al₅O₁₂ (x=0, 0.1, 0.2, 0.3, 0.4) ceramics were prepared by solid-state reaction at 1600 °C for 10 h. The microstructure, thermophysical properties and phase stability under high temperature were investigated. The results showed that all the Yb doped (Y_1-xYb_x)₃Al₅O₁₂ ceramics were comprised of a single garnet-type Y₃Al₅O₁₂ phase. The thermal conductivities of (Y_1-xYb_x)₃Al₅O₁₂ ceramics firstly decreased and subsequently increased with Yb ions concentration rising from room temperature to 1200 °C. (Y_0.7Yb_0.3)₃Al₅O₁₂ had the lowest thermal conductivity among investigated specimens, which was about 1.62 W m⁻¹ K⁻¹ at 1000 °C, around 30% lower than that of pure YAG (2.3 W m⁻¹ K⁻¹, 1000 °C). Yb had almost no effect on the coefficients of thermal expansion (CTEs) of (Y_1-xYb_x)₃Al₅O₁₂ ceramics and the CTE was approximate 10.7×10⁻⁶ K⁻¹ at 1200 °C. In addition, (Y_0.7Yb_0.3)₃Al₅O₁₂ ceramic remained good phase stability when heating from room temperature to 1450 °C.     

Microwave dielectric properties of silico-carnotite Ca3M2Si3O12 (M= Yb,Y) ceramics synthesized via high energy ball milling

The Ca₃M₂Si₃O₁₂ (M = Yb, Y) ceramics with orthorhombic silico-carnotite structure were fabricated via high-energy ball milling and solid-state reaction route. Dense Ca₃Yb₂Si₃O₁₂ and Ca₃Y₂Si₃O₁₂ ceramics sintered at 1260 °C and 1240 °C revealed promising microwave dielectric properties with ε_r = 9.2 and 8.7, Q×f = 56,400 GHz and 29,094 GHz, τ_f = −77.5 ppm/°C and −76.8 ppm/°C, respectively. The connection between crystal structure and Q×f values of Ca₃M₂Si₃O₁₂ (M = Yb, Y) ceramics was discussed with respect to the packing fraction, and their intrinsic microwave dielectric properties were examined using the infrared reflectivity spectra analysis. The thermal stability of Ca₃Yb₂Si₃O₁₂ was improved successfully by forming 0.91Ca₃Yb₂Si₃O₁₂‐0.09CaTiO₃ composite ceramics with τ_f = +2.9 ppm/°C, ε_r = 12.93 and Q×f = 26,729 GHz.     

Structural-phase state and lasing of 5–15 at% Yb3+:Y3Al5O12 optical ceramics

Yttrium aluminum garnet (Yb³⁺:Y₃Al₅O₁₂) laser ceramics doped by 5, 10 and 15 at% of ytterbium ions were obtained by reactive sintering. Optimal sintering temperature range for the formation of highly-dense transparent Yb³⁺:Y₃Al₅O₁₂ ceramics under normal recrystallization conditions was found to be T = 1750–1800 °C. The influence of Yb³⁺ ions on structural-phase state, phase composition, microstructure, optical and luminescent properties of sintered samples was experimentally investigated. It was shown that lattice parameter a of Yb³⁺:Y₃Al₅O₁₂ ceramics decreases linearly with increasing of Yb³⁺ concentration in a good agreement with L. Vegard’s rule, that indicates to the formation of (Y_1−xYb_x)₃Al₅O₁₂ (х = 0.05–0.15) substitutional solid solutions. No concentration quenching of Yb³⁺ luminescence was observed in Yb³⁺:Y₃Al₅O₁₂ within the 5–15 at% doping range. Quasi-CW lasing of Yb³⁺:Y₃Al₅O₁₂ ceramics was studied under diode-pumping at 970 nm. A highest slope efficiency of about 50% was obtained for 15 at%-doped Yb³⁺:Y₃Al₅O₁₂ ceramics sintered at T = 1800 °C for 10 h.     

Estimation of Sc3+ solubility in dodecahedral and octahedral sites in YSAG:Yb

A method for synthesizing YSAG:Yb optical ceramics has been developed. Additionally, the phase composition and unit cell parameters for YSAG, YbSAG, and their solid solutions have been determined. The limits of scandium solubility in the dodecahedral and octahedral sites of garnet crystal lattice have been estimated after annealing at 1600°C. The scandium solubility limit in the dodecahedral sites of YSAG:Yb was found to be 66 ± 2 at.%. The limit of scandium solubility in octahedral sites depended upon the type of garnet-forming cations. The solubility limit for Sc³⁺ decreased from 97.5 ± 0.5 to 68.5 ± 1 at.% with simultaneous increase of ytterbium content in the YSAG-YbSAG system. Therefore, the region of solid solutions existing with a garnet structure in the Al₂O₃–Sc₂O₃–Yb₂O₃–Y₂O₃ system was determined. Samples having scandium in both dodecahedral and octahedral sites, which had a Sc³⁺ content of ~30 at.%, were synthesized as a precursor for optical ceramic production.     

A3Y2Ge3O12 (A = Ca,Mg): Two novel microwave dielectric ceramics with contrasting τf and Q × f

Two garnet-structured microwave dielectric ceramics of A₃Y₂Ge₃O₁₂ (A = Ca, Mg; called CYG and MYG, respectively) were synthesized. CYG was crystallized in a normal cubic garnet structure with Ca²⁺ fully occupying the dodecahedral (A) site, whereas MYG was an inverse garnet with mixed distribution of Mg²⁺/Y³⁺ at the A site. The difference in ionic occupation resulted in anomalies in microwave dielectric properties, with dielectric constant (ε_r) = 14.1, quality factor (Q × f) = 12,600 GHz and positive temperature coefficient of resonant frequency (τ_f) =120.5 ppm/°C for MYG ceramic and ε_r = 10.8, Q × f = 97,126 GHz and τ_f = −40.6 ppm/°C for CYG ceramic. The large deviations in measured ε_r from theoretical ε_th possibly resulted from the garnet structural constraints leading to ‘rattling’ Mg²⁺ and Y³⁺ in A site of MYG. Infrared reflectivity spectra analysis revealed ion polarization contributed mostly to the permittivity of both ceramics in microwave frequency ranges.     

Effect of Y2O3 content on the microstructural characteristics and the mechanical and thermal properties of Yb-doped SiAlON ceramics

SiAlON ceramics are primarily employed in ceramic cutting tools, which exploit their stable physical properties in high-temperature cutting environments due to their excellent mechanical properties. Here, Yb/Y-co-doped SiAlON ceramics are prepared by adding Yb and Y rare-earth (RE) ions in the RE_xSi_12-(m+n)Al_m+nO_nN_16-n (m = 0.4, n = 1.0) composition. Yb₂O₃, the RE oxide, is the main sintering additive. For RE_x composition design with (Yb_1-y + Y_y)_x, Yb₂O₃ is replaced by Y₂O₃ (y = 0.00, 0.25, 0.50, 0.75, 1.00). While Yb₂O₃ has excellent high-temperature stability, it is limited by its microstructural characteristics, that is, the β-SiAlON morphology and limited fracture toughness due to the small cation sizes. Thus, the changes in the above properties are investigated for various Y₂O₃ additive contents substituting for Yb₂O₃. The average grain width decreases, and the equiaxed β-SiAlON grains are elongated with increasing Y₂O₃ content. Regarding the mechanical properties, the hardness and fracture toughness are evaluated using the indentation fracture method. The hardness decreases with increasing Y₂O₃ content; however, the fracture toughness exhibits a significant increase (～53.6%) from 4.6 to 7.0 MPa?m^1/2. Regarding crack propagation, intergranular fracture is mainly observed in the Yb/Y-co-doped SiAlON ceramics, whereas transgranular fracture is primarily observed in the Yb-single-doped SiAlON ceramic. Y₂O₃ substitution increases the α/β-SiAlON phase ratio, and the grain boundary phase exhibits increasing vitrification with increasing Y₂O₃ content. Moreover, the thermal properties of the Yb/Y-co-doped compositions are analyzed and discussed regarding intrinsic properties such as phonon scattering. The microstructural characteristics and improved fracture toughness derived from the Yb/Y-co-doped system designed in this study suggest considerable potential for the future composition design of ceramic cutting tools.     

Tunability of τf in garnet-structured Y3Ga5O12 microwave dielectric ceramics

The τ_f of Y₃Ga₅O₁₂ ceramics was adjusted by Ca²⁺/Ti⁴⁺ co-doping for Y³⁺ at A-site and Ga³⁺ at C-site to form Ca_xY_3-xTi_xGa_5-xO₁₂ (0 ≤ x ≤ 2.0) ceramics by the solid-state reaction. When 0 ≤ x ≤ 1.7, all the samples remained as single garnet-structured with Ia-3d space group. The ε_r increased from 10.4 ± 0.1 to 15.9 ± 0.1, and τ_f optimized from −54.7 ± 1.0 to −8.3 ± 1.0 ppm/℃, attributing to the increase in polarizability per volume and “rattling” effect. Meanwhile, the Q × f slightly decreased from 98,200 ± 500 GHz to 65,300 ± 500 GHz due to the decrease in packing fraction. As x increased to 2.0, the properties dramatically deteriorated owing to the second phase CaTiO₃. Optimal properties were obtained at x = 1.7, with ε_r = 15.9 ± 0.1, Q × f = 65,300 ± 500 GHz and τ_f = −8.3 ± 1.0 ppm/℃.     

Comparative study of Yb:Lu3Al5O12 and Yb:Lu2O3 laser ceramics produced from laser-ablated nanopowders

We present a comparative study of two Lu-based oxide ceramics doped with Yb³⁺ ions, namely Yb:Lu₃Al₅O₁₂ (garnet) and Yb:Lu₂O₃ (sesquioxide), promising for thin-disk lasers. The ceramics are fabricated using nanopowders of 3.6 at.% Yb:Lu₂O₃ and Al₂O₃ produced by laser ablation: Yb:Lu₃Al₅O₁₂ – by vacuum sintering at 1800 °C for 5 h with the addition of 1 wt% TEOS as a sintering aid, and Yb:Lu₂O₃ – by vacuum pre-sintering at 1250 °C for 2 h followed by Hot Isostatic Pressing at 1400 °C for 2 h under Ar gas pressure of 207 MPa. The comparison includes the structure, Raman spectra, transmission, optical spectroscopy and laser operation. The crystal-field splitting of Yb³⁺ multiplets is revealed for Lu₃Al₅O₁₂. A continuous-wave (CW) Yb:Lu₃Al₅O₁₂ ceramic microchip laser generates 5.65 W at 1031.1 nm with a slope efficiency of 67.2%. In the quasi-CW regime, the peak power is scaled up to 8.83 W. The power scaling for the Yb:Lu₂O₃ ceramic laser is limited by losses originating from residual coloration and inferior thermal behavior.     

Fabrication,microstructure, and optical properties of Yb:Y3ScAl4O12 transparent ceramics with different doping levels

Transparent Yb:Y₃ScAl₄O₁₂ (Yb:YSAG) ceramics with different ytterbium doping concentrations such as 5, 10, 15, 20 at.% have been successfully fabricated by solid-state reactive sintering. All the obtained ceramics are in dense and homogeneous structure after sintering at 1820°C for 30 hours and with a posttreatment by hot isostatic pressing at 1750°C for 3 hours with 200 MPa pressure. We systematically analyzed the influence of Yb³⁺ doping concentration on the microstructure and optical properties of the ceramics. The 10 at.% Yb:Y₃ScAl₄O₁₂ ceramics with a thickness of 3.2 mm show the best transparency as high as 80.9% at 1100 nm. The laser emission of the 10 at.% Yb:YSAG ceramics was tested, resulting in a maximum slope efficiency of 67.6% and a maximum output power of 11.3 W under quasi-continuous wave pump conditions. The tuning range spanned from 990 to 1071 nm.     

The effect of Ga addition on the sinterability and microwave dielectric properties of RE3Al5O12 (Tb,Y, Er and Yb) garnet ceramics

The RE₃Al₅O₁₂ (RE=Tb, Y, Er, Yb) ceramics have been prepared by the mixed oxide route and the influence of Ga³⁺ doping on their properties is investigated. The intrinsic Y₃Al₅O₁₂ (YAG) ceramic sintered at 1650 °C for 4 h showed good dielectric properties; (ε_r=10.1, Q_u×f=65,000 GHz, τ_f=−45 ppm/°C). Addition of Ga₂O₃ was found to be beneficial in improving the densification of Tb₃Al₅O₁₂, Er₃Al₅O₁₂ and Yb₃Al₅O₁₂ except Y₃Al₅O₁₂ where Nb₂O₅ is the better choice. Among Ga³⁺ added samples, the composition Yb₃Al₅O₁₂+1 wt% Ga₂O₃ showed good microwave dielectric properties: ε_r=10.3, Q_u×f=50,000 GHz, τ_f=−58 ppm/°C. The Y₃Al₅O₁₂ doped with 1 wt% Nb₂O₅ has ε_r=10.7, Q_u×f=120,000 GHz and τ_f=−45 ppm/°C. The ceramics have good thermal properties (CTE=2–3 ppm/°C, λ=2–12 W/m K).     

Transparent ultrafine Yb3+:Y2O3 laser ceramics fabricated by spark plasma sintering

Conventional ceramic processing techniques do not produce ultrafine‐grained materials. However, since the mechanical and optical properties are highly dependent on the grain size, advanced processing techniques are needed to obtain ceramics with a grain size smaller than the wavelength of visible light for new laser sources. As an empirical study for lasing from an ultrafine‐grained ceramics, transparent Yb³⁺:Y₂O₃ ceramics with several doping concentrations were fabricated by spark plasma sintering (SPS) and their microstructures were analyzed, along with optical and spectroscopic properties. Laser oscillation was verified for 10 at.% Yb³⁺:Y₂O₃ ceramics. The laser ceramics in our study were sintered without sintering additives, and the SPS produced an ultrafine microstructure with an average grain size of 261 nm, which is about one order of magnitude smaller than that of ceramics sintered by conventional techniques. A load was applied during heating to enhance densification, and an in‐line transmittance near the theoretical value was obtained. An analysis of the crystal structure confirmed that the Yb³⁺:Y₂O₃ ceramics were in a solid solution. To the best of our knowledge, this study is the first report verifying the lasing properties of not only ultrafine‐grained but also Yb‐doped ceramics obtained by SPS.     

Phase composition,microstructure and thermophysical properties of the Srx(Zr0.9Y0.05Yb0.05)O1.95+x ceramics

Sr_x(Zr_0.9Y_0.05Yb_0.05)O_1.95+x (x=1.0, 0.9, 0.8, 0.7) ceramics were prepared by solid state reaction sintering. The sintered Sr_1.0(Zr_0.9Y_0.05Yb_0.05)O_2.95 is a single-phase solid solution while the sintered Sr_x(Zr_0.9Y_0.05Yb_0.05)O_1.95+x (x=0.9?0.7) are composites, and a significant grain growth inhibition is observed in the sintered Sr_x(Zr_0.9Y_0.05Yb_0.05)O_1.95+x (x=1.0, 0.9). Rare-earth elements distribution in the bulk materials indicates that Yb and Y preferentially substitute Zr-sites in SrZrO₃, and the highest solubility of RE₂O₃ in pure SrZrO₃ is ～0.8 mol%. The sintered Sr_x(Zr_0.9Y_0.05Yb_0.05)O_1.95+x have high thermal expansion coefficients up to ～11.0×10^?6 K^-1 (1200°C). Sr_0.8(Zr_0.9Y_0.05Yb_0.05)O_2.75 has the lowest thermal conductivity of 1.38 W·m^-1·K^-1 at 800°C. Sr_x(Zr_0.9Y_0.05Yb_0.05)O_1.95+x (x=1.0, 0.9, 0.8) show no phase transition from 600 to 1400°C, whereas Sr_x(Zr_0.9Y_0.05Yb_0.05)O_1.95+x (x=0.9, 0.8) have excellent high-temperature phase stability over the whole investigated temperature range. Therefore, Sr_x(Zr_0.9Y_0.05Yb_0.05)O_1.95+x (x=1.0, 0.9, 0.8) are considered as promising TBCs materials that might be operated at higher temperatures compared to YSZ.     

Relationship between Rattling Mg2+ ions and anomalous microwave dielectric behavior in Ca3-xMg1+xLiV3O12 ceramics with garnet structure

Ca_3-xMg_1+xLiV₃O₁₂ (0 ≤ x ≤ 1) ceramics with cubic-garnet-structure were synthesized by the solid-phase reaction. The replacement of Ca²⁺ with the smaller Mg²⁺ exerted an increasingly strong “rattling” effect at the A-site of Ca_3-xMg_1+xLiV₃O₁₂. With increased Mg²⁺, ε_r increased from 10.5 ± 0.1 to 15.4 ± 0.1 and ε_corr increased from 11.0 ± 0.1 to 16.0 ± 0.1, whereas the theoretical ε_th decreased from 12.0 ± 0.1 to 10.5 ± 0.1. ε_corr was higher than ε_th due to the “rattling” effect. The enhanced “rattling” effect caused τ_f to increase rapidly from –64.1 ± 1.0 ppm/°C to +267.2 ± 1.0 ppm/°C. With increased x, Q × f decreased from 74,700 ± 500 GHz to 15,370 ± 500 GHz, due to the decreased packing fraction, increased FWHM of the A_1g modes, and enhanced “rattling” effect. Additionally, the chemical compatibility between Ca_2.75Mg_1.25LiV₃O₁₂ and Ag electrodes was confirmed, indicating this material’s potential for LTCC.     

Carbonate-precipitation synthesis of Yb:Y2O3 nanopowders and its characteristics

Ytterbium-doped yttria (Yb³⁺:Y₂O₃) nanopowders for transparent ceramics were synthesized by using a carbonate-precipitation method. The characteristics of precursor and powders calcined at different temperatures were investigated. The pure yttria phase can form through calcining at 700 °C. The Yb³⁺:Y₂O₃ nanopowders calcined at 1100 °C were well dispersed with a spherical morphology, and had a narrow particle size distribution with a mean particle size of about 70 nm. By using 1100 °C-calcined powders, nearly full dense Yb³⁺:Y₂O₃ ceramics were fabricated at 1750 °C for 8 h without any additives under vacuum conditions. The fluorescence spectrum of the sintered ceramics illustrates that there are two emission peaks locating at 1028 and 1071 nm respectively, all corresponding to the ²F_5/2 → ²F_7/2 transitions of Yb³⁺ ion. Homogeneous Yb³⁺:Y₂O₃ nanopowders synthesized by carbonate-precipitation method are suitable for the fabrication of IR-transparent ceramics.     

Color tuning of Lu3Al5O12:Dy3+ ceramic-based white light-emitting phosphors via Yb incorporation

Transparent Lu₃Al₅O₁₂:Dy³⁺ ceramics were fabricated for UV-pumped white light-emitting diodes (WLEDs) via solid-state sintering under vacuum. The color chromaticity of the ceramic-based phosphors were tuned by tailoring the Dy³⁺ concentration and incorporating Yb into the crystal lattice to form (Lu, Yb)₃Al₅O₁₂:Dy³⁺ solid solutions. Phase composition, microstructure, optical and photoluminescence properties of the ceramics were investigated in detail by X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV–vis-NIR spectrometer and fluorescence spectrophotometer, respectively. White light can be obtained by combining the UV-chip and the structure/property-optimized ceramic phosphors. The color hue was tuned from (0.4107, 0.4037) to (0.3647, 0.3299) with the increasing Yb content from 0 to 0.5 substituting Lu sites in the garnet structure. The (Lu_0.5Yb_0.5)₃Al₅O₁₂: 0.01Dy³⁺ ceramic-based phosphor showed a relative low correlated color temperature of 4137 K. The decrease in PL intensities with Yb incorporation was also discussed via microstructure and fluorescence lifetime characterizations.     

Tb3+/Yb3+ co-doped Y2O3 upconversion transparent ceramics: Fabrication and characterization for IR excited green emission

Tb³⁺/Yb³⁺ co-doped Y₂O₃ transparent ceramics were fabricated by vacuum sintering of the pellets (prepared from nanopowders by uniaxial pressing) at 1750 °C for 5 h. Zr⁴⁺ and La³⁺ ions were incorporated in Tb³⁺/Yb³⁺ co-doped Y₂O₃ nanoparticle to reduce the formation of pores which limits the transparency of ceramic. An optical transmittance of ∼80% was achieved in ∼450 to 2000 nm range for 1 mm thick pellet which is very close to the theoretical value by taking account of Fresnel’s correction. High intensity luminescence peak at 543 nm (green) was observed in these transparent ceramics under 976 and 929 nm excitations due to Yb–Tb energy transfer upconversion.     

Highly transparent Yb:Y2O3 ceramics obtained by solid-state reaction and combined sintering procedures

(Y_0.87-xLa_0.1Zr_0.03Yb_x)₂O₃ (x?=?0.02, 0.04, 0.05) transparent ceramics were obtained by solid-state reaction and combined sintering procedures with La₂O₃ and ZrO₂ as sintering additives. A method based on two-step intermediate sintering in air followed by vacuum sintering was applied in order to control the densification and grain growth of the samples during the final sintering process. The results indicate that La₂O₃ and ZrO₂ co-additives can improve the microstructure and optical properties of Yb:Y₂O₃ ceramics at relatively low sintering temperature. On the other hand, the addition of Zr⁴⁺ ions leads to the formation of dispersed scattering volumes in the ceramic bodies. Transmittance of 78.8% was measured for the 2.0?at% Yb:Y₂O₃ ceramic sample at the wavelength of 1100?nm. The spectroscopic properties of Yb:Y₂O₃ ceramics were investigated at room temperature. The obtained results show that the absorption cross-section at 978?nm is in the range of 2.08?×?10^–20 to 2.36?×?10^–20 cm², whereas the emission cross-section at 1032?nm is ~1.0?×?10^–20 cm².     

Electrical resistivity of Si3N4 ceramics with Yb2O3 additive

Si₃N₄ ceramics with excellent mechanical properties are used for heat dissipation substrates and so on. In order to improve their reliability and expand their application fields, it is desirable to understand and control the electrical properties of Si₃N₄ ceramics. In this study, the electrical resistivity of Si₃N₄ ceramics with Yb₂O₃ additive was investigated by applying various voltages at temperatures ranging from 25°C to 300°C. When Yb₂O₃ was added as a sintering aid to Si₃N₄ ceramics, a crystalline J-phase (Yb₄Si₂O₇N₂) was formed and their electrical resistivity was significantly lower than that of Y₂O₃ additive. The electrical resistivity of the Yb₂O₃-added ceramics decreased with an increase in temperature and applied voltage. Yb existed in multiple valence states, Yb²⁺ and Yb³⁺, in the Si₃N₄ ceramics and the decrease in the electrical resistivity can be attributed hopping conduction through the J-phase. The J-phase in the Si₃N₄ ceramics was observed to be continuous, and percolation analysis suggested that the J-phase formed an infinite cluster. Therefore, the decrease in the electrical resistivity of the Yb₂O₃-added Si₃N₄ ceramics was found mainly to result from the formation of an infinite cluster of J-phase, which exhibits hopping conduction.     

A new series of low-temperature cofirable Li3Ba2La3(1-x)Y3x(MoO4)8 microwave dielectric ceramics

A new series of Li₃Ba₂La_3(1-x)Y_3x(MoO₄)₈ microwave dielectric ceramics were prepared by a conventional solid-state reaction method. The Rietveld refinement results further confirm that Li₃Ba₂La_3(1-x)Y_3x(MoO₄)₈ belongs to a monoclinic system with space group C2/c. Scanning electron microscopy results reveal that Li₃Ba₂La_3(1-x)Y_3x(MoO₄)₈ ceramics can be well sintered at a low sintering temperature. In addition, the permittivity (ε_r) of Li₃Ba₂La_3(1-x)Y_3x(MoO₄)₈ ceramics was found to decrease gradually with increasing substitution content of Y³⁺, while the quality factor (Qxf) and temperature coefficient of resonant frequency (τ_f) increase with x monotonously. The x?=?0.4 ceramic sintered at 700?°C for 4?h possesses optimum microwave dielectric properties of ε_r ～ 14.4, Qxf ～ 14,994?GHz (at 9.0?GHz) and τ_f ～?+?6.9?ppm/°C. Particularly, no chemical reaction between the matrix phase and Ag metal suggests that the Li₃Ba₂La_1.8Y_1.2(MoO₄)₈ ceramic might be a promising candidate for low-temperature co-fired ceramic applications.