Microwave dielectric characterization of Ca0.6(La1-xYx)0.2667TiO3 perovskite ceramics with high positive temperature coefficient

Lin, Shih-Hung; Lin, Zi-Qi; Chen, Chi‐Wei

doi:10.1016/j.ceramint.2021.02.256

Cited by 11 publications

(4 citation statements)

References 28 publications

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“…In order to meet the requirements of device miniaturization, microwave dielectric ceramics having medium/high relative dielectric constants (ε r ) have been the focus of researches [6,7], including TiO 2 [8,9], Ba 6−3x Ln 8+2x Ti 18 O 54 (BLT, where Ln = rare earth element) [10,11], CaO-Li 2 O-Ln 2 O 3 -TiO 2 [12,13], Ca 1−x Ln 2x/3 TiO 3 (CLT) [14][15][16], lead-based perovskite [17,18], etc. In recent years, BLT with a tungsten-bronze structure and CLT with a perovskite structure have been extensively studied [19][20][21][22][23][24]. Meanwhile, novel ceramic systems such as Bi 2 (Li 0.5 Ta 1.5 )O 7 [25,26] and BiVO 4 [27,28] have also been developed.…”

Section: Introduction mentioning

confidence: 99%

Structure, defects, and microwave dielectric properties of Al-doped and Al/Nd co-doped Ba4Nd9.33Ti18O54 ceramics

Guo

Luo

et al. 2022

J Adv Ceram

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Low-loss tungsten—bronze microwave dielectric ceramics are dielectric materials with potential application value for miniaturized dielectric filters and antennas in the fifth-generation (5G) communication technology. In this work, a novel Al/Nd co-doping method of Ba4Nd9.33Ti18O54 (BNT) ceramics with a chemical formula of Ba4Nd9.33+z/3Ti18−zAlzO54 (BNT—AN, 0 ≼ z ≼ 2) was proposed to improve the dielectric properties through structural and defect modulation. Together with Al-doped ceramics (Ba4Nd9.33Ti18−zAl4z/3O54, BNT—A, 0 ≼ z ≼ 2) for comparison, the ceramics were prepared by a solid state method. It is found that Al/Nd co-doping method has a significant effect on improving the dielectric properties compared with Al doping. As the doping amount z increased, the relative dielectric constant (εr) and the temperature coefficient of resonant frequency (τf) of the ceramics decreased, and the Q×f values of the ceramics obviously increased when z ≼ 1.5. Excellent microwave dielectric properties of εr = 72.2, Q×f = 16,480 GHz, and τf = +14.3 ppm/°C were achieved in BNT—AN ceramics with z = 1.25. Raman spectroscopy and thermally stimulated depolarization current (TSDC) technique were firstly combined to analyze the structures and defects in microwave dielectric ceramics. It is shown that the improvement on Q×f values was originated from the decrease in the strength of the A-site cation vibration and the concentration of oxygen vacancies $$\text{V}_\text{O}^{^{ \cdot \cdot }}$$, demonstrating the effect and mechanism underlying for structural and defect modulation on the performance improvement of microwave dielectric ceramics.

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Section: Introduction mentioning

confidence: 99%

Structure, defects, and microwave dielectric properties of Al-doped and Al/Nd co-doped Ba4Nd9.33Ti18O54 ceramics

Guo

Luo

et al. 2022

J Adv Ceram

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“…Na 2 MoO 4 ceramic have been found to have low dielectric loss (high Q × f = 35000 ± 1000 GHz) and large TCF ∼ −76 ± 3 ppm/ • C. 24 Y 2 O 3 was usually employed as a normal dopant for low permittivity materials, and the ionic radius of Y 3+ (1.019 Å) was close to that of Na + (1.18 Å) at the A-site. [25][26][27] Thus, in this work, (NaY) 1/2 MoO 4 was fabricated via solid-state reaction, and the microwave dielectric properties, densities, phases, and microstructures of the ceramics at different temperatures were investigated.…”

Section: Introductionmentioning

confidence: 99%

Microwave dielectric properties of tetragonal scheelite‐structured (NaY)_1/2MoO₄ ceramics

Wang

Pang

Zhou

et al. 2023

Int J Applied Ceramic Tech

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(NaY)1/2MoO4 was fabricated via the solid‐state reaction method of Na2CO3, Y2O3, and MoO3. Scanning electron microscopy results demonstrated that all the (NaY)1/2MoO4 ceramics could be densified well in the sintering temperature range of 900–960°C. Results of X‐ray diffraction analysis demonstrated that the (NaY)1/2MoO4 ceramics crystallized into tetragonal scheelite structure. Sintering (NaY)1/2MoO4 at 940°C for 2 h optimized the microwave dielectric properties of the ceramics. The microwave permittivity, Q × f, and TCF of the (NaY)1/2MoO4 were 10.9, 29 000 GHz and −40.7 ppm/°C, respectively.

show abstract

“…In order to meet the requirements of device miniaturization, microwave dielectric ceramics having medium/high relative dielectric constant (ε r ) have been a focus of research [6], including TiO 2 [7,8], Ba 6 − 3x Ln 8+2x Ti 18 O 54 (BLT, where Ln = rare earth element) [9,10], CaO-Li 2 O-Ln 2 O 3 -TiO 2 [11,12], Ca 1 − x Ln 2x/3 TiO 3 (CLT) [13][14][15], lead-based perovskite [16,17], etc. In recent years, BLT with a tungsten-bronze structure and CLT with a perovskite structure have been extensively studied [18][19][20][21][22][23]. Meanwhile, novel ceramic systems such as Bi 2 (Li 0.5 Ta 1.5 )O 7 [24,25] and BiVO 4 [26,27] have also been developed.…”

Section: Introductionmentioning

confidence: 99%

Structure, Defects and Microwave Dielectric Properties of Al-Doped and Al/Nd Co-doped Ba4Nd9.33Ti18O54 Ceramics

Guo

Luo

et al. 2021

Preprint

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Low-loss tungsten-bronze microwave dielectric ceramics are a kind of dielectric materials with potential application value for miniaturized dielectric filters and antennas in 5G communication technology. In this work, a novel Al/Nd co-doping method of Ba4Nd9.33Ti18O54 (BNT) ceramics with a chamical formula of Ba4Nd9.33+z/3Ti18-zAlzO54 (BNT-AN, 0 ≤ z ≤ 2) was proposed to improve the dielectric properties through structural and defect modulation. Together with Al-doped ceramics (Ba4Nd9.33Ti18-zAl4z/3O54, BNT-A, 0 ≤ z ≤ 2) for comparison, the ceramics were prepared by solid state method. It is found that Al/Nd co-doping method has a significant effect on improving the dielectric properties compared with Al doping. As the doping amount z increased, the relative dielectric constant (εr) and the temperature coefficient of resonant frequency (τf) of the ceramics decreased, and the Q×f values of the ceramics obviously increased when z ≤ 1.5. Excellent microwave dielectric properties of εr = 72.2, Q×f = 16480 GHz, and τf = +14.3 ppm/℃ were achieved in BNT-AN ceramics with z = 1.25. Raman spectroscopy and thermally stimulated depolarization current (TSDC) technique were firstly combined to analyze the structure and defects in the dielectric ceramics. It is shown that the improvement on Q×f values were origined from the decrease in the strength of the A-site cation vibration and the concentration of oxygen vacancies (Vö), demonstrating the effect and mechanism underlying for structural and defect modulation on the performance improvement of microwave dielectric ceramics.

show abstract

Microwave dielectric characterization of Ca0.6(La1-xYx)0.2667TiO3 perovskite ceramics with high positive temperature coefficient

Cited by 11 publications

References 28 publications

Structure, defects, and microwave dielectric properties of Al-doped and Al/Nd co-doped Ba4Nd9.33Ti18O54 ceramics

Structure, defects, and microwave dielectric properties of Al-doped and Al/Nd co-doped Ba4Nd9.33Ti18O54 ceramics

Microwave dielectric properties of tetragonal scheelite‐structured (NaY)_1/2MoO₄ ceramics

Structure, Defects and Microwave Dielectric Properties of Al-Doped and Al/Nd Co-doped Ba4Nd9.33Ti18O54 Ceramics

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Microwave dielectric characterization of Ca0.6(La1-xYx)0.2667TiO3 perovskite ceramics with high positive temperature coefficient

Cited by 11 publications

References 28 publications

Structure, defects, and microwave dielectric properties of Al-doped and Al/Nd co-doped Ba4Nd9.33Ti18O54 ceramics

Structure, defects, and microwave dielectric properties of Al-doped and Al/Nd co-doped Ba4Nd9.33Ti18O54 ceramics

Microwave dielectric properties of tetragonal scheelite‐structured (NaY)1/2MoO4 ceramics

Structure, Defects and Microwave Dielectric Properties of Al-Doped and Al/Nd Co-doped Ba4Nd9.33Ti18O54 Ceramics

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Microwave dielectric properties of tetragonal scheelite‐structured (NaY)_1/2MoO₄ ceramics