Dielectric properties of FeNbO4 ceramics prepared by the sol-gel method

Devesa, Susana; Graça, M.P.F.; Henry, F.; Costa, L.C.

doi:10.1016/j.solidstatesciences.2016.09.005

Cited by 24 publications

(22 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The samples treated at 500, 650, 1050, and 1150°C possess peaks at 102, 450, and 687 cm In the spectra presented in Figure 5(b), all the detected bands are attributed vibrations of the base units of the monoclinic FeNbO 4 phase. The Nb─O stretching bands were observed at 276, 394, 597, and 818 cm −1 , and the bands visible at 365 and 467 cm −1 are exclusively for the monoclinic FeNbO 4 [35][36][37][38]. With the increase of the temperature, it can be seen a better definition of bands, which is consistent with the increase of the crystallinity of the samples.…”

Section: Raman Spectroscopy Analysissupporting

confidence: 73%

Sol-Gel Synthesis, Structural Characterization and Microwave Dielectric Properties of Bismuth Niobate Modified by Iron Inclusion

Devesa¹,

Graça²,

Costa³

2017

Recent Applications in Sol-Gel Synthesis

View full text Add to dashboard Cite

The current progress in communication technologies is leading to extensive studies on the development of miniaturized electronic devices with high electromagnetic performances, reliability, and low cost. Contributing to this purpose, the development and study of new materials, with promising electric properties in radio and microwave ranges, have been subject of our research in particular niobate-based materials. Bismuth niobate, BiNbO 4 , is a low-firing ceramic that has been studied for a variety of applications in the microelectronic industry. In this work, the microwave dielectric characterization of (Bi 1−x Fe x )NbO 4 (0.00 ≤ x ≤ 1.00) samples, prepared by the sol-gel method and heat treated at specific temperatures, is performed and related with their structure and morphology. The structural data were obtained by X-ray diffraction and Raman spectroscopy and the morphology by scanning electron microscopy. The dielectric characterization in the microwave region was made using the small perturbation theory, with a resonant cavity operating in TE 105 mode, at the frequency of 2.7 GHz. The results show that the sol-gel method has the advantage of allowing the formation of α-BiNbO 4 phase at lower temperatures when compared with conventional preparation methods, and that the inclusion of iron inhibits the formation of low-and high-temperature β-BiNbO 4 phases.

show abstract

Section: Raman Spectroscopy Analysissupporting

confidence: 73%

Sol-Gel Synthesis, Structural Characterization and Microwave Dielectric Properties of Bismuth Niobate Modified by Iron Inclusion

Devesa¹,

Graça²,

Costa³

2017

Recent Applications in Sol-Gel Synthesis

View full text Add to dashboard Cite

show abstract

“…These measurements were made using a precision impedance analyser (Agilent 4294A) in the Cp-Rp configuration, in the temperature range of 200-400 K. The real part of the complex permittivity, ε´, and the imaginary part, ε", were calculated using Eq. (1) [22]:…”

Section: Experimental Methodsmentioning

confidence: 99%

Dielectric Properties of Bismuth Niobate Ceramics

Devesa¹,

Graça²,

CadillonCosta³

2018

Bismuth - Advanced Applications and Defects Characterization

View full text Add to dashboard Cite

The development of new dielectric materials that allow the reduction of size and weight of electronic components has been in the scope of the researchers. The bismuth-based dielectric ceramics are extensively studied for this purpose, namely, the bismuth niobate (BiNbO 4). The first attempt to improve BiNbO 4 occurred in 1992 when Kagata reported the microwave dielectric properties of bismuth niobate doped with the addition of oxides. This chapter will present a brief review of the several attempts that have been carried out to enhance the dielectric properties of BiNbO 4 by modifying their structure through addition, doping, or atom(s) substitution. This manuscript focuses on a case study that involves bismuth substitution by europium ions. To investigate the inclusion of europium in BiNbO 4 ceramics, (Bi 1-x Eu x)NbO 4 samples were prepared using the sol-gel method, in particular, the citrate route. The structure of the prepared samples was studied by X-ray diffraction (XRD) and Raman spectroscopy and the morphology by scanning electron microscopy (SEM). The dielectric properties were studied, in the microwave frequency range (MW), using the resonant cavity method, and in the radio frequency range (RF), with the impedance spectroscopy technique.

show abstract

“…Devesa et al prepared FeNbO 4 powders using the sol-gel method, being observed the formation of the monoclinic phase in the sintered pellets. Fe 2 O 3 was detected as an impurity in the range of temperature of 100-500°C, while at 1200°C, single-phase sample was obtained 11 . Nanospheres of an orthorhombic structure were synthesized by Shim et al 12 using a hydrothermal process at 250°C, obtained with uniform size, in the range of 5-10 nm and a large specific surface area (82.72 m 2 g -1 ).…”

Section: Introductionmentioning

confidence: 96%

“…Recently, there has been an increasing interest in some types of ABO 4 oxides as catalysts, including iron niobate, FeNbO 4 . This compound has also been investigated for the applications as a photodetector, in solar energy conversion, as gas sensor, as photocatalyst and as electrode material for Li-ion batteries [10][11][12][13][14] . These compound have three crystalline forms: a wolframitetype (space group p2/c) with a monoclinic symmetry which exists below 1085°C.…”

Section: Introductionmentioning

confidence: 99%

“…It is also reported a fourth phase that crystallizes in the AlNbO 4 -type structure (space group C2/m) with a monoclinic symmetry, stable at 700°C. The degree of the cation order depends on the specific conditions of synthesis 10,11,13,15,16 . The preparation of the FeNbO 4 powders in most reported works involves solid-state reactions, which generally required long periods of mechanical mixing and high heat treatment temperature to obtain the desired phase, however with low surface area 13 .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Nanoparticles of FeNbO4 Produced by Microwave Assisted Combustion Reaction: A Potential Technology for the Treatment of Wastewater

et al. 2020

View full text Add to dashboard Cite

Iron(III) niobate, FeNbO 4 , was synthesized for the first time by microwave-assisted combustion reaction between Fe(NO 3) 3 .9H 2 O and NH 4 [NbO(C 2 O 4) 2 (H 2 O) 2 ](H 2 O) in the presence of NH 4 NO 3 and Urea {O=C(NH 2) 2 }. Experiments of X-ray powder diffraction revealed a small crystallite size for this material, 16 nm, and the results of MEV showed that it forms agglomerates with diameters between 80 and 180 nm with spherical shapes. HRTEM images revealed that the material is formed by clusters of particles with a diameter near 20 nm. A surface area of 40 m 2 g-1 was determined by experiments of specific surface area (SSA). The FeNbO 4 induced the decomposition of H 2 O 2 , forming radicals that, in turn, discoloured Indigo dye Carmine (IC) a solution. The results showed that this niobate was able to degrade 55% of the initial solution in the presence of H 2 O 2 after 360 minutes of reaction time.

show abstract

Dielectric properties of FeNbO4 ceramics prepared by the sol-gel method

Cited by 24 publications

References 26 publications

Sol-Gel Synthesis, Structural Characterization and Microwave Dielectric Properties of Bismuth Niobate Modified by Iron Inclusion

Sol-Gel Synthesis, Structural Characterization and Microwave Dielectric Properties of Bismuth Niobate Modified by Iron Inclusion

Dielectric Properties of Bismuth Niobate Ceramics

Nanoparticles of FeNbO4 Produced by Microwave Assisted Combustion Reaction: A Potential Technology for the Treatment of Wastewater

Contact Info

Product

Resources

About