Microwave dielectric properties of Ba3.75Nd9.5Ti18−zCr4z/3O54 ceramics

Tang, Bin; Xiang, Qiuyuan; Fang, Zixuan; Guo, Xia; Zhang, Shuren

doi:10.1007/s10854-017-7944-9

Cited by 13 publications

(11 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure shows the surface micromorphology of the BSNT‐ z Al ceramics. Obviously, the grains show a rod‐like morphology for all BSNT‐ z Al ceramics, which is similar to previous reports on tungsten bronze‐type microwave dielectric ceramics . The grain size decreases with increasing z value, indicating that the density of the grain boundaries increases.…”

Section: Resultssupporting

confidence: 88%

“…As z increases from 0 to 2.5, ε r decreases from 87.12 to 63.37. According to Shannon's rule and relevant reports on Ti‐based systems, ε r is directly related to the ionic polarizability (α D) and the molecular volume ( V m ):

a_{D} = \frac{V_{m} (ε_{rc} - 1)}{b (ε_{rc} + 2)}

where ε rc is the corrected dielectric constant and b is a constant equal to 4π/3. According to Equation (), ε rc increased when α D increases or V m decreases.…”

Section: Resultsmentioning

confidence: 99%

“…For Ti‐based microwave dielectric ceramics, it has been demonstrated that low‐valence element substitutions (such as Al, Mg, Cr) for Ti could effectively improve Q × f values . In the present work, the substitution of Al 3+ for Ti 4+ was assumed to achieve a high Q × f value and a near‐zero τ f for Ba 4 (Sm 0.15 Nd 0.85 ) 9.33 Ti 18 O 54 (BSNT) ceramics.…”

Section: Introductionmentioning

confidence: 93%

“…However, the Q × f values of current microwave dielectric ceramics still do not meet the requirements for 5G communication. Many attempts have been made to improve the Q × f values of microwave dielectric ceramics, such as introducing dopants to form solid solutions, using nonstoichiometric effects, and adding foreign components with higher Q × f values . However, the related microwave dielectric loss mechanism remains unclear, and the increase in Q × f values is often accompanied by the deterioration of other properties (especially ε r ) .…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Microwave dielectric properties and thermally stimulated depolarization of Al‐doped Ba₄(Sm,Nd)_9.33Ti₁₈O₅₄ ceramics

et al. 2019

View full text Add to dashboard Cite

Ba4(Sm0.15Nd0.85)9.33Ti18‐zAl3z/4O54 (BSNT‐zAl, 0.0 ≤ z ≤ 2.5) ceramics were prepared via a solid‐state reaction, and the effects of Al doping on the microwave dielectric properties and defect behavior of the title compound were studied. X‐ray diffraction (XRD) analysis and scanning electron microscopy (SEM) photographs suggested that Al ions successfully entered the lattice to form tungsten‐bronze‐like solid solutions. With a small amount of Al substitution, the relative dielectric constant (εr), and the temperature coefficient of resonant frequency (τf) values decreased, whereas the quality factor (Q × f) substantially increased by approximately 50%. The defect‐related extrinsic dielectric loss was clarified via the thermally stimulated depolarization current (TSDC) technique. With Al doping, the TSDC relaxation of across‐grain‐boundary oxygen vacancies (VO..) vanished, whereas that of defect dipoles (AlTi′-VO..) appeared at relatively low temperatures. Therefore, in the BSNT‐zAl ceramics, oxygen vacancies were more inclined to interconnect with AlTi′ to form defect dipoles. This could reduce the activity of VO.. and account for the notable improvement in the Q × f values. In particular, the excellent characteristics of εr = 67.33, Q × f = 16 530 GHz, and τf = +0.87 ppm/°C were achieved in the specimens with z = 1.5 sintered at 1350°C for 4 hours.

show abstract

Section: Resultssupporting

confidence: 88%

a_{D} = \frac{V_{m} (ε_{rc} - 1)}{b (ε_{rc} + 2)}

where ε rc is the corrected dielectric constant and b is a constant equal to 4π/3. According to Equation (), ε rc increased when α D increases or V m decreases.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Microwave dielectric properties and thermally stimulated depolarization of Al‐doped Ba₄(Sm,Nd)_9.33Ti₁₈O₅₄ ceramics

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Many studies revealed that TCF could be adjusted effectively by the substitution for B‐site (Ti 4+ ) in Ba 6−3 x Nd 8+2 x Ti 18 O 54 and Ba 6−3 x La 8+2 x Ti 18 O 54 ceramics system, such as Al 3+ , Cr 3+ , Zr 4+ , (Al 1/2 Nb 1/2 ) 4+ , (Cr 1/2 Nb 1/2 ) 4+ , (Zn 1/3 Nb 2/3 ) 4+ , and so on . Tang et al reported Cr 3+ or (Cr 1/2 Nb 1/2 ) 4+ instead of Ti 4+ in Ba 3.75 Nd 9.5 Ti 18 O 54 could adjust the TCF to near zero, but the Qf was seriously deteriorated. Guo et al reported Al 3+ instead of Ti 4+ could effectively reduce the TCF and improve the Qf in Ba 4 (Sm 0.15 Nd 0.85 ) 9.33 Ti 18 O 54 ceramics.…”

Section: Introductionmentioning

confidence: 99%

Novel thermally stable, high quality factor Ba₄(Pr_0.4Sm_0.6)_28/3Ti₁₈₋_yGa₄_y_/3O₅₄ microwave dielectric ceramics

Wang

Shi

et al. 2019

J Am Ceram Soc

View full text Add to dashboard Cite

High dielectric constant Ba4(Pr0.4Sm0.6)28/3Ti18−yGa4y/3O54 (BPSTG) (0 ≤ y ≤ 1) microwave ceramics with enhanced dielectric properties were synthesized via the traditional solid‐state processing for the first time. The crystal structure, microstructure, and microwave dielectric characteristics were investigated in details. X‐ray diffraction results showed that all well‐sintered samples belonged to a single tungsten bronze type phase. Results showed that partial substitution of Ga3+ for Ti4+ is an effective way in adjusting the temperature coefficient of resonant frequency (TCF) value of the Ba4(Pr0.4Sm0.6)28/3Ti18O54 ceramics and increased the quality factor (Qf) values. The variation tendency of dielectric constant was in accordance with the ionic polarizability. The Qf values highly depend on the grain size from the scanning electron microscopy results. A near zero TCF value can be obtained by carefully adjusting the substitution of Ga3+ content. Infrared reflectivity (FIR) spectra were employed to reveal the relationship between the phonons and microwave dielectric properties. At last, excellent combinations dielectric properties of εr = 78.5, Qf = 12,400 GHz, TCF = +2.1 ppm/°C were achieved in BPSTG ceramics when y = 0.75.

show abstract

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

View full text Add to dashboard Cite

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.

show abstract

Microwave dielectric properties of Ba3.75Nd9.5Ti18−zCr4z/3O54 ceramics

Cited by 13 publications

References 17 publications

Microwave dielectric properties and thermally stimulated depolarization of Al‐doped Ba₄(Sm,Nd)_9.33Ti₁₈O₅₄ ceramics

Microwave dielectric properties and thermally stimulated depolarization of Al‐doped Ba₄(Sm,Nd)_9.33Ti₁₈O₅₄ ceramics

Novel thermally stable, high quality factor Ba₄(Pr_0.4Sm_0.6)_28/3Ti₁₈₋_yGa₄_y_/3O₅₄ microwave dielectric ceramics

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

Contact Info

Product

Resources

About

Microwave dielectric properties of Ba3.75Nd9.5Ti18−zCr4z/3O54 ceramics

Cited by 13 publications

References 17 publications

Microwave dielectric properties and thermally stimulated depolarization of Al‐doped Ba4(Sm,Nd)9.33Ti18O54 ceramics

Microwave dielectric properties and thermally stimulated depolarization of Al‐doped Ba4(Sm,Nd)9.33Ti18O54 ceramics

Novel thermally stable, high quality factor Ba4(Pr0.4Sm0.6)28/3Ti18−yGa4y/3O54 microwave dielectric ceramics

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

Contact Info

Product

Resources

About

Microwave dielectric properties and thermally stimulated depolarization of Al‐doped Ba₄(Sm,Nd)_9.33Ti₁₈O₅₄ ceramics

Microwave dielectric properties and thermally stimulated depolarization of Al‐doped Ba₄(Sm,Nd)_9.33Ti₁₈O₅₄ ceramics

Novel thermally stable, high quality factor Ba₄(Pr_0.4Sm_0.6)_28/3Ti₁₈₋_yGa₄_y_/3O₅₄ microwave dielectric ceramics