High permittivity and low loss dielectric ceramics in the BaO–La2O3–TiO2–Ta2O5 system

Chen, X.M; Sun, Yong; Zheng, X. H.

doi:10.1016/s0955-2219(02)00372-2

Cited by 99 publications

(29 citation statements)

References 10 publications

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“…Interest on tungsten bronze structured dielectric ceramics in polycrystalline or single crystal form has increased considerably because of their interesting properties for device applications [1][2][3][4][5][6] 30 , consisting complex array of distorted BO 6 octahedra sharing corners providing three different interstices (A 1 , A 2 , B 1 , B 2 and C) for cation substitution. Due to the complex structure, its physical properties can be tailored through suitable cation substitutions, but these physical properties are also dependent on the synthesis route, environment and time of formation.…”

Section: Introductionmentioning

confidence: 99%

Frequency dependent electrical properties of Na2Pb2R2W2Ti4Nb4O30 (R = Nd, Sm) ceramics

2014

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Abstract:In the present research work, frequency dependent electrical properties of tungsten bronze structured compounds Na 2 Pb 2 R 2 W 2 Ti 4 Nb 4 O 30 (R = Nd, Sm) are reported. X-ray diffraction (XRD) study of polycrystalline ceramic samples confirms the formation of compounds with orthorhombic structure. Analysis of frequency dependent electrical data in the framework of modulus and conductivity formalism suggests the presence of thermally activated relaxation process in the compounds, which show Arrhenius behavior. The magnitudes of activation energies give the nature of the relaxing species. The real and imaginary parts of complex modulus trace the depressed semicircle in complex plane, suggesting non-Debye type relaxation process in the materials. The power law behavior of admittance data is successfully modeled by introducing constant phase element (CPE) to the equivalent circuit. A large value of power law parameter (n) of CPE below ferroelectric transition temperature (T c ) is attributed to the cooperative response of the dipoles which is reduced above T c . This behavior is correlated with the frequency dependence of CPE, suggesting a physical meaning to it. The frequency dependent AC conductivity at different temperatures follows Jonscher's universal power law. Almond and West formalism is used to estimate the hopping rate, activation enthalpy and charge carrier concentration in the materials.

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Section: Introductionmentioning

confidence: 99%

Frequency dependent electrical properties of Na2Pb2R2W2Ti4Nb4O30 (R = Nd, Sm) ceramics

2014

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“…Recently, owing to the rapid progress in microwave telecommunications, satellite broadcasting, and other related technologies, a number of Ba based TB compounds with dielectric constant nearly 100 have attracted much attention because of their importance in the miniaturization of microelectronic devices [6][7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Structural, dielectric, electrical and piezoelectric properties of Ba4SrRTi3V7O30 (R=Sm, Dy) ceramics

Sahoo¹,

Panigrahi²,

Patri³

et al. 2008

Open Physics

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Abstract:Polycrystalline samples of Ba 4 SrRTi 3 V 7 O 30 (R=Sm and Dy), members of the tungsten-bronze family, were prepared using a high-temperature, solid-state reaction technique and studied their electrical properties (using complex impedance spectroscopy) in a wide range of temperature (31-500 • C) and frequency (1 kHz -1 MHz). Preliminary structural (XRD) analyses of these compounds show the formation of single-phase, orthorhombic structures at room temperature. The scanning electron micrographs (SEM) provided information on the quality of the samples and uniform distribution of grains over the entire surface of the samples. Detailed studies of the dielectric properties suggest that they have undergone ferroelectric-paraelectric phase transition well above the room temperatures (i.e., 432 and 355 • C for R= Sm and Dy, respectively, at frequency 100 kHz). Measurements of electrical conductivity (ac and dc) as a function of temperature suggest that the compounds have semiconducting properties much above the room temperature, with negative temperature coefficient of resistance (NTCR) behavior. The existence of ferroelectricity in these compounds was confirmed from a polarization study.

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“…Some paraelectric niobates and with high dielectric constant and low loss are also very important due to the rapid progress in microwave telecommunications, satellite broadcasting and L. Fang [7][8][9]. The TB structure consists of a complex array of distorted BO 6 octahedra sharing corners in such a way that three different types of interstices (A, B and C) are available for a wide variety of cations occupying in the general formula (A 1 ) 2 (A 2 ) 4 (C) 4 (B 1 ) 2 (B 2 ) 8 O 30 [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

“…In order to find some new filled tungsten-bronze ceramics, some works have been carried out in quaternary systems containing rare earths [6][7][8][9][10][11]. Sebastian and Chen et al proposed some promising candidates for high dielectric constant (ε > 100) dielectric ceramics with filled tungstenbronze structure in BaO-Ln 2 O 3 -TiO 3 -M 2 O 5 system (Ln = La, Sm, Nd; M = Ta, Nb) [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

“…Sebastian and Chen et al proposed some promising candidates for high dielectric constant (ε > 100) dielectric ceramics with filled tungstenbronze structure in BaO-Ln 2 O 3 -TiO 3 -M 2 O 5 system (Ln = La, Sm, Nd; M = Ta, Nb) [7][8][9][10]. We recently conducted the systematic studies on the preparation and dielectric properties of Sr-based TB ceramics such as Sr 5 LnTi 3 Ta 7 O 30 and Sr 4 Ln 2 Ti 4 Ta 6 O 30 [12][13][14][15], Sn-contained ceramics A 5 LnSn 3 Nb 7 O 30 (A = Ba, Sr) [16,17], and Zn-contained TB ceramics Ba 5 LnZnM 9 O 30 (M = Ta, Nb) [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

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Characterization and dielectric properties of Ba5LnNiTa9O30 (Ln = La, Nd and Sm) ceramics

et al. 2006

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Three novel Ba 5 LnNiTa 9 O 30 (Ln = La, Nd and Sm) ceramics were prepared and characterized in the BaO-Ln 2 O 3 -NiO-Ta 2 O 5 system. All three compounds adopted the filled tetragonal tungsten bronze (TB) structure at room temperature. The present ceramics exhibited relaxor behavior, and the Curie temperature (at 10kHz) were −130, -80 and -45 • C for Ba 5 LaNiTa 9 O 30 , Ba 5 NdNiTa 9 O 30 , and Ba 5 SmNiTa 9 O 30 respectively. At room temperature, Ba 5 LnNiTa 9 O 30 ceramics have a high dielectric constants in the range 102∼118, a low dielectric loss in range 0.0019∼0.0036, and the temperature coefficients of the dielectric constant (τ ε ) in the range -320∼−460 ppm • C −1 (at 1 MHz).

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High permittivity and low loss dielectric ceramics in the BaO–La2O3–TiO2–Ta2O5 system

Cited by 99 publications

References 10 publications

Frequency dependent electrical properties of Na2Pb2R2W2Ti4Nb4O30 (R = Nd, Sm) ceramics

Frequency dependent electrical properties of Na2Pb2R2W2Ti4Nb4O30 (R = Nd, Sm) ceramics

Structural, dielectric, electrical and piezoelectric properties of Ba4SrRTi3V7O30 (R=Sm, Dy) ceramics

Characterization and dielectric properties of Ba5LnNiTa9O30 (Ln = La, Nd and Sm) ceramics

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