Effects of lanthanides on structural and dielectric properties of NdNbO4-LnNbO4 ceramics

Zhao, Yonggui; Zhang, Ping

doi:10.1016/j.ceramint.2017.10.136

Cited by 17 publications

(9 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As can be seen from Figure 11 , deep minima are observed in the infrared spectra about 470, 670, and 810 cm −1 , which are characteristic of rare-earth metal orthoniobates. Features of vibrational spectra of products of heterophase substitution of lithium-ion in metaniobate by ions of rare earth metals are consistent with recent literature data [ 44 , 53 , 54 ].…”

Section: Resultssupporting

confidence: 90%

Molten Chlorides as the Precursors to Modify the Ionic Composition and Properties of LiNbO3 Single Crystal and Fine Powders

et al. 2022

View full text Add to dashboard Cite

Modifying lithium niobate cation composition improves not only the functional properties of the acousto- and optoelectronic materials as well as ferroelectrics but elevates the protonic transfer in LiNbO3-based electrolytes of the solid oxide electrochemical devices. Molten chlorides and other thermally stable salts are not considered practically as the precursors to synthesize and modify oxide compounds. This article presents and discusses the results of an experimental study of the full or partial heterovalent substitution of lithium ion in nanosized LiNbO3 powders and in the surface layer of LiNbO3 single crystal using molten salt mixtures containing calcium, lead, and rare-earth metals (REM) chlorides as the precursors. The special features of heterovalent ion exchange in chloride melts are revealed such as hetero-epitaxial cation exchange at the interface PbCl2-containing melt/lithium niobate single crystal; the formation of Li(1−x) Ca(x/2)V(x/2)Li+ NbO3 solid solutions with cation vacancies as an intermediate product of the reaction of heterovalent substitution of lithium ion by calcium in LiNbO3 powders; the formation of lanthanide orthoniobates with a tetragonal crystal structure such as scheelite as the result of lithium niobate interaction with trichlorides of rare-earth elements. It is shown that the fundamental properties of ion-modifiers (ion radius, nominal charge), temperature, and duration of isothermal treatment determine the products’ chemical composition and the rate of heterovalent substitution of Li+-ion in lithium niobate.

show abstract

Section: Resultssupporting

confidence: 90%

Molten Chlorides as the Precursors to Modify the Ionic Composition and Properties of LiNbO3 Single Crystal and Fine Powders

et al. 2022

View full text Add to dashboard Cite

show abstract

“…The microwave dielectric properties ( ε r , Q × f , and TCF values) of the RENbO 4 ceramics as a function of A-site ionic radius are shown in Figure . These data are selected from papers published in recent years. ,,− ,,, The permittivity of the RENbO 4 ceramics with M-fergusonite structure was stabilized at 17–22, showing little dependence on the ionic radius, except for the Bi 0.99 Sm 0.01 NbO 4 (orthorhombic phase) ceramics in the red circle. The Q × f values, ranging from 30 000 to 80 000, are divergent.…”

Section: Resultsmentioning

confidence: 99%

“…Lanthanides are considered to be the most promising substituents as they have a similar ionic radius. Zhang et al investigated the performance of the (Nd 0.94 RE 0.06 )NbO 4 (RE = Ce, Gd–Er, and Yb) ceramics in the microwave band, achieving low loss and, unfortunately, poor thermal stability. They − also studied the (Nd 1– x RE x )NbO 4 (RE = Sm, La, and Y) microwave dielectric ceramics and explained the correlation between the crystal structure and the dielectric properties by the generalized P–V–L theory.…”

Section: Introductionmentioning

confidence: 99%

“…papers published in recent years. 5,9,[11][12][13][14]16,37,38 The permittivity of the RENbO 4 ceramics with M-fergusonite structure was stabilized at 17−22, showing little dependence on the ionic radius, except for the Bi 0.99 Sm 0.01 NbO 4 (orthorhombic phase) ceramics in the red circle. The Q × f values, ranging from 30 000 to 80 000, are divergent.…”

Section: ■ Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Design of a Sub-6 GHz Dielectric Resonator Antenna with Novel Temperature-Stabilized (Sm_1–xBi_x)NbO₄ (x = 0–0.15) Microwave Dielectric Ceramics

Zhou

et al. 2022

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Microwave dielectric ceramics exhibiting a low dielectric constant (ε r ), high quality factor (Q × f), and thermal stability, specifically in an ultrawide temperature range (from −40 to +120 °C), have attracted much attention. In addition, the development of 5G communication has caused an urgent demand for electronic devices, such as dielectric resonant antennas. Hence, the feasibility of optimizing the dielectric properties of the SmNbO4 (SN) ceramics by substituting Bi3+ ions at the A site was studied. The permittivity principally hinges on the contribution of Sm/Bi–O to phonon absorption in the microwave range, while the reduced sintering temperature results in a smaller grain size and slightly lower Q × f value. The expanded and distorted crystal cell indicates that Bi3+ doping effectively regulates the temperature coefficient of resonant frequency (TCF) by adjusting the strains (causing the distorted monoclinic structure) of monoclinic fergusonite besides correlating with the permittivity. Moreover, a larger A-site radius facilitates the acquisition of near-zero TCF values. Notably, the (Sm0.875Bi0.125)NbO4 (SB0.125N) ceramic with ε r ≈ 21.9, Q × f ≈ 38 300 GHz (at ∼8.0 GHz), and two different near-zero TCF values of −9.0 (from −40 to +60 °C) and −6.6 ppm/°C (from +60 to +120 °C), respectively, were obtained in the microwave band. A simultaneous increase in the phase transition temperature (T c) and coefficients of thermal expansion (CTEs) by A-site substitution provides the possibility for promising thermal barrier coating (TBC) materials. Then, a cylindrical dielectric resonator antenna (CDRA) with a resonance at 4.86 GHz and bandwidth of 870 MHz was fabricated by the SB0.125N specimen. The exceptional performance shows that the SB0.125N material is a possible candidate for the sub-6 GHz antenna owing to the advantages of low loss and stable temperature.

show abstract

“…It is worth noting that the modes below 180 cm −1 could not be identified here, likely due to the filter used to remove the contribution of the Rayleigh scattering during the collection of the Raman signal. Nevertheless, 4 additional small peaks that were not reported by those authors (or others [ 7 , 19 , 21 ]) are also present in the displayed spectra, specifically at 501, 520, 547, and 777 cm −1 . The origin of these peaks is not yet clear.…”

Section: Resultsmentioning

confidence: 62%

Tuning Green to Red Color in Erbium Niobate Micro- and Nanoparticles

et al. 2021

View full text Add to dashboard Cite

Tetragonal Er0.5Nb0.5O2 and monoclinic ErNbO4 micro- and nanoparticles were prepared by the citrate sol–gel method and heat-treated at temperatures between 700 and 1600 °C. ErNbO4 revealed a spherical-shaped crystallite, whose size increased with heat treatment temperatures. To assess their optical properties at room temperature (RT), a thorough spectroscopic study was conducted. RT photoluminescence (PL) spectroscopy revealed that Er3+ optical activation was achieved in all samples. The photoluminescence spectra show the green/yellow 2H11/2, 4S3/2→4I15/2 and red 4F9/2→4I15/2 intraionic transitions as the main visible recombination, with the number of the crystal field splitting Er3+ multiplets reflecting the ion site symmetry in the crystalline phases. PL excitation allows the identification of Er3+ high-energy excited multiplets as the preferential population paths of the emitting levels. Independently of the crystalline structure, the intensity ratio between the green/yellow and red intraionic transitions was found to be strongly sensitive to the excitation energy. After pumping the samples with a resonant excitation into the 4G11/2 excited multiplet, a green/yellow transition stronger than the red one was observed, whereas the reverse occurred for higher excitation photon energies. Thus, a controllable selective excited tunable green to red color was achieved, which endows new opportunities for photonic and optoelectronic applications.

show abstract

Effects of lanthanides on structural and dielectric properties of NdNbO4-LnNbO4 ceramics

Cited by 17 publications

References 38 publications

Molten Chlorides as the Precursors to Modify the Ionic Composition and Properties of LiNbO3 Single Crystal and Fine Powders

Molten Chlorides as the Precursors to Modify the Ionic Composition and Properties of LiNbO3 Single Crystal and Fine Powders

Design of a Sub-6 GHz Dielectric Resonator Antenna with Novel Temperature-Stabilized (Sm_1–xBi_x)NbO₄ (x = 0–0.15) Microwave Dielectric Ceramics

Tuning Green to Red Color in Erbium Niobate Micro- and Nanoparticles

Contact Info

Product

Resources

About

Effects of lanthanides on structural and dielectric properties of NdNbO4-LnNbO4 ceramics

Cited by 17 publications

References 38 publications

Molten Chlorides as the Precursors to Modify the Ionic Composition and Properties of LiNbO3 Single Crystal and Fine Powders

Molten Chlorides as the Precursors to Modify the Ionic Composition and Properties of LiNbO3 Single Crystal and Fine Powders

Design of a Sub-6 GHz Dielectric Resonator Antenna with Novel Temperature-Stabilized (Sm1–xBix)NbO4 (x = 0–0.15) Microwave Dielectric Ceramics

Tuning Green to Red Color in Erbium Niobate Micro- and Nanoparticles

Contact Info

Product

Resources

About

Design of a Sub-6 GHz Dielectric Resonator Antenna with Novel Temperature-Stabilized (Sm_1–xBi_x)NbO₄ (x = 0–0.15) Microwave Dielectric Ceramics