In this paper we have used the hydrothermal process to synthesize Pb(Fe1/2Nb1/2)O3 ceramics at re... more In this paper we have used the hydrothermal process to synthesize Pb(Fe1/2Nb1/2)O3 ceramics at relatively low temperature. KOH alkaline solution favors the solubility of the precursors in their solid form. The obtained product was put into an autoclave and heat treated at 180°C for 24H. The recovered powder was then heat treated at different temperatures to obtain the pure perovskite phase. Reproducibility of the experiment was successfully checked. Microstructure of the samples was analysed with a scanning electron microscope (SEM), and dielectric measurements were performed using an impedance analyser (LCR, HP 4284 A) in the frequency range from 20 Hz to 1MHz.
IOP Conference Series: Materials Science and Engineering
In this work, the Pb (Zr 0.52Ti 0.48)1-3x/4Fe x O3 (x=0.0; 0.025; 0.05; 0.075; 0.10; 0.15; 0.20) ... more In this work, the Pb (Zr 0.52Ti 0.48)1-3x/4Fe x O3 (x=0.0; 0.025; 0.05; 0.075; 0.10; 0.15; 0.20) ceramics were synthesized by using the sol-gel method. X-ray diffraction (XRD), Raman spectra, was used to reach the structural properties of the studied compounds. The XRD patterns registered at room temperature revealed the phase formation of the samples which was confirmed by the Rietveld refinement method which suggests the formation of mixed tetragonal and rhombohedral phases. Raman spectra show that when iron content increases, the intensity of Raman peaks of pure PZT increases. The dielectric properties of Pb (Zr 0.52Ti 0.48)1-3x/4Fe x (PZTFx) materials as a function of temperature are studied and displayed a resonance phenomenon for all samples which is moved to the higher frequencies combined with a decrease in dielectric constant when Fe concentration increase. The variation of the dielectric constant as a function of temperature at low frequencies reveals a shifting of the tra...
The organic–inorganic hybrid perovskite-like [C<sub>6</sub>H<sub>5</sub>C... more The organic–inorganic hybrid perovskite-like [C<sub>6</sub>H<sub>5</sub>C<sub>2</sub>H<sub>4</sub>NH<sub>3</sub>]<sub>2</sub>ZnCl<sub>4</sub> (PEA-ZnCl<sub>4</sub>) was synthesized by saturated solutions method. X-ray powder diffraction, Raman spectroscopy, UV-visible transmittance, and capacitance meter measurements have been used to characterize the structure, the functional groups, the optical parameters, and the dielectric constants of the material. The material has a layered structure. The optical transmittance (T %) was recorded and applied to deduce the absorption coefficient (α) and optical band gap (Eg). The hybrid shows an insulator character with a direct band gap about 4.46 eV, and presents high dielectric constants up to a frequency of about 10<sup>5</sup> Hz, which suggests a ferroelectric behavior. The reported optical and dielectric properties can help to under...
In this work, the influence of zinc doping on structural and dielectric properties of CaCu(3-x)Zn... more In this work, the influence of zinc doping on structural and dielectric properties of CaCu(3-x)ZnxTi4O12 (CCZxTO with x = 0, 2.5, 5, 7.5, 10, 12.5 and 15%) ceramics sintered at 1000 ºC for 8 h was studied. The ceramic samples were prepared by the conventional solid-state and calcined at 1050 ºC for 4 h. The X-ray diffraction (XRD) analysis of pure and Zn-doped CCTO were analyzed by using Rietveld refinement with cubic CCTO phase with no trace impurity phase. The scanning electron microscopy (SEM) investigation showed that for Zn-doped CCTO, the grains distributions were homogenous with average sizes which decreased with increasing of Zn concentration. The dielectric permittivity as function of temperature showed two dielectric anomalies (weakly and strong) and the dielectric constant value largely decreased for x = 2.5%, which is about tree magnitude smaller than the pure ceramic. Then it increased and reached a maximum at x = 10%, which is larger than the value of pure ceramic. And...
The effect of doping sol gel processed (Ba 1-x Sr x )TiO 3 (BST) samples with Cerium (Ce), on bot... more The effect of doping sol gel processed (Ba 1-x Sr x )TiO 3 (BST) samples with Cerium (Ce), on both structural and dielectric properties, is investigated. XRD measurements show that the samples crystallize in a pseudo cubic phase with the presence of secondary phases. SEM Micrographs revealed that introduction of Ce decreases the grain size; the latter is quite uniform. Moreover, Ce reduces the permittivity of the samples, and an anomaly is observed above 300°C.
Compositions of La-modified lead zirconate titanate ceramics (PLZT, % La: 0, 0.03, 0.12, 0.20) ne... more Compositions of La-modified lead zirconate titanate ceramics (PLZT, % La: 0, 0.03, 0.12, 0.20) near the morphotropic boundary phase (MPB) have been prepared using the hydrothermal process. Characterizations using x-ray diffraction (XRD) and scanning electron microscopy (SEM) have shown that the raw powders present a crystalline structure and exhibit a mixed phase - tetragonal and rhombohedral phases - under heating, and that these powders consist in small particles. Besides, Ladoping have led to a lowering of the temperature of the maximum of the dielectric constant and to an increase of this maximum.
Les poudres ceramiques de titanate de plomb, dopees au lanthane La (PLT), et / ou au fer Fe (PFxT... more Les poudres ceramiques de titanate de plomb, dopees au lanthane La (PLT), et / ou au fer Fe (PFxT ou PLyFxT), de structure perovskite, ont ete preparees par voie sol-gel en adoptant le mode de la destabilisation de solution colloidale (DSC). L'effet de la temperature sur les echantillons a ete etudie par spectroscopie infrarouge a transformee de Fourier (IRTF). L'effet du dopage en La ou Fe sur la structure cristalline a ete examine par diffraction des rayons X (DRX) et par spectroscopie Raman. Nous avons choisi d'effectuer les mesures dielectriques sur trois echantillons pour voir l'effet d'un faible dopage en fer et d'un fort dopage en lanthane sur les proprietes dielectriques des materiaux PbTiO 3 .
La-modified lead zirconate titanate ( PZT) ceramics have been prepared using the hydrothermal pro... more La-modified lead zirconate titanate ( PZT) ceramics have been prepared using the hydrothermal process. Temperature effect on PLZT powders has been studied using TGA-TDA technics, Fourier Transform Infrared (FTIR) spectroscopy, and X-Ray Diffraction (XRD).Dielectric measurements have also been performed. Crystallization temperature has been found to be inferior to that reported in the literature, relative to analogous compounds prepared using other methods. All the obtained results have been discussed and compared to those reported in the literature.
As a lead-free ceramic, lanthanum-modified barium titanate (BLT) has attracted significant attent... more As a lead-free ceramic, lanthanum-modified barium titanate (BLT) has attracted significant attention among researchers in recent years due to its interesting ferroelectric and piezoelectric properties and insulating behavior, which can be improved by the doping effect. For that, (Ba0.7La0.3) (Ti1−xNix)O3 (where x = 0%, 1%, 3%, 5%, 7% or 10%), denoted as BLTNx, were synthesized via the sol-gel process. The effect of the divalent ion Ni2+ on the structural, microstructural and dielectric properties was investigated by x-ray diffraction (XRD) and Fourier transform infrared (FTIR), Raman, and impedance spectroscopy (IS). Surface morphology analysis is done by scanning electronic microscopy (SEM). Dielectric properties were determined in the ranges 28°C to 400°C and 1 kHz to 2 MHz. The results showed that a low doping amount of Ni (x < 5%) increases the dielectric constant. The sample with x = 5% exhibited, at 400°C, a relatively high dielectric constant (ɛ′ = 2202), the sample with x = 3% exhibited, at 100°C, low dielectric loss (tan(δ) = 0.009), and high insulating character, indicating a suitable material for multilayer ceramic capacitors (MLCCs) and energy storage.
In this paper, composite ceramics (1-x)CaCu3Ti4O12–(x)PbZr0.48Ti0.52O3 (with x =0.00, 0.50 and ... more In this paper, composite ceramics (1-x)CaCu3Ti4O12–(x)PbZr0.48Ti0.52O3 (with x =0.00, 0.50 and 1.00), denoted CCTO-PZT, were prepared by a three-stages modified method, in order to achieve high dielectric constant and low loss. Structural investigations carried out by X-ray diffraction (XRD), and FT-IR spectroscopy showed the formation of pure cubic and tetragonal phases for x = 0.00 and x=1.00 compositions, respectively. XRD showed the coexistence of both phases in the CCTO-PZT composite. The morphology of the ceramics was examined by scanning electron micrograph (SEM), results reveal a homogeneous microstructure with two types of grains corresponding to PZT (smaller grains) and CCTO (large grains). Dielectric measurements carried out by an impedance analyzer; show that the dielectric constant of the CCTO-PZT composite is higher than the pure samples (CCTO and PZT) one. The temperature dependence of the ac conductivity indicated that the conduction follows the Arrhenius law and t...
Structural and microstructural properties of sol gel processed BS x T (x = 0.0, 0.05) ceramics ha... more Structural and microstructural properties of sol gel processed BS x T (x = 0.0, 0.05) ceramics have been investigated. Dielectric properties of these ceramics have also been studied as functions of frequency [1kHz-2MHz] at different measurement temperatures (30-200° C). Heat treatment duration effect on dielectric properties and structural ones has been investigated. The results show that heat treatment and its duration has significant effects on structural, dielectric properties and the average grain size of the samples. Scanning electron microscopy (SEM) analysis show quite regular morphology of the grains and an average grain size which decreases with introduction of Sr, in agreement with structural characterization. Raman analysis has given results which are in accordance of XRD and SEM characterizations. Moreover, the permittivity variations as functions of the frequency, show a decrease in the interval [1kHz-100kHz], followed by an anormal increase in the interval [100kHz-1MHz].
In this paper we have used the hydrothermal process to synthesize Pb(Fe1/2Nb1/2)O3 ceramics at re... more In this paper we have used the hydrothermal process to synthesize Pb(Fe1/2Nb1/2)O3 ceramics at relatively low temperature. KOH alkaline solution favors the solubility of the precursors in their solid form. The obtained product was put into an autoclave and heat treated at 180°C for 24H. The recovered powder was then heat treated at different temperatures to obtain the pure perovskite phase. Reproducibility of the experiment was successfully checked. Microstructure of the samples was analysed with a scanning electron microscope (SEM), and dielectric measurements were performed using an impedance analyser (LCR, HP 4284 A) in the frequency range from 20 Hz to 1MHz.
IOP Conference Series: Materials Science and Engineering
In this work, the Pb (Zr 0.52Ti 0.48)1-3x/4Fe x O3 (x=0.0; 0.025; 0.05; 0.075; 0.10; 0.15; 0.20) ... more In this work, the Pb (Zr 0.52Ti 0.48)1-3x/4Fe x O3 (x=0.0; 0.025; 0.05; 0.075; 0.10; 0.15; 0.20) ceramics were synthesized by using the sol-gel method. X-ray diffraction (XRD), Raman spectra, was used to reach the structural properties of the studied compounds. The XRD patterns registered at room temperature revealed the phase formation of the samples which was confirmed by the Rietveld refinement method which suggests the formation of mixed tetragonal and rhombohedral phases. Raman spectra show that when iron content increases, the intensity of Raman peaks of pure PZT increases. The dielectric properties of Pb (Zr 0.52Ti 0.48)1-3x/4Fe x (PZTFx) materials as a function of temperature are studied and displayed a resonance phenomenon for all samples which is moved to the higher frequencies combined with a decrease in dielectric constant when Fe concentration increase. The variation of the dielectric constant as a function of temperature at low frequencies reveals a shifting of the tra...
The organic–inorganic hybrid perovskite-like [C<sub>6</sub>H<sub>5</sub>C... more The organic–inorganic hybrid perovskite-like [C<sub>6</sub>H<sub>5</sub>C<sub>2</sub>H<sub>4</sub>NH<sub>3</sub>]<sub>2</sub>ZnCl<sub>4</sub> (PEA-ZnCl<sub>4</sub>) was synthesized by saturated solutions method. X-ray powder diffraction, Raman spectroscopy, UV-visible transmittance, and capacitance meter measurements have been used to characterize the structure, the functional groups, the optical parameters, and the dielectric constants of the material. The material has a layered structure. The optical transmittance (T %) was recorded and applied to deduce the absorption coefficient (α) and optical band gap (Eg). The hybrid shows an insulator character with a direct band gap about 4.46 eV, and presents high dielectric constants up to a frequency of about 10<sup>5</sup> Hz, which suggests a ferroelectric behavior. The reported optical and dielectric properties can help to under...
In this work, the influence of zinc doping on structural and dielectric properties of CaCu(3-x)Zn... more In this work, the influence of zinc doping on structural and dielectric properties of CaCu(3-x)ZnxTi4O12 (CCZxTO with x = 0, 2.5, 5, 7.5, 10, 12.5 and 15%) ceramics sintered at 1000 ºC for 8 h was studied. The ceramic samples were prepared by the conventional solid-state and calcined at 1050 ºC for 4 h. The X-ray diffraction (XRD) analysis of pure and Zn-doped CCTO were analyzed by using Rietveld refinement with cubic CCTO phase with no trace impurity phase. The scanning electron microscopy (SEM) investigation showed that for Zn-doped CCTO, the grains distributions were homogenous with average sizes which decreased with increasing of Zn concentration. The dielectric permittivity as function of temperature showed two dielectric anomalies (weakly and strong) and the dielectric constant value largely decreased for x = 2.5%, which is about tree magnitude smaller than the pure ceramic. Then it increased and reached a maximum at x = 10%, which is larger than the value of pure ceramic. And...
The effect of doping sol gel processed (Ba 1-x Sr x )TiO 3 (BST) samples with Cerium (Ce), on bot... more The effect of doping sol gel processed (Ba 1-x Sr x )TiO 3 (BST) samples with Cerium (Ce), on both structural and dielectric properties, is investigated. XRD measurements show that the samples crystallize in a pseudo cubic phase with the presence of secondary phases. SEM Micrographs revealed that introduction of Ce decreases the grain size; the latter is quite uniform. Moreover, Ce reduces the permittivity of the samples, and an anomaly is observed above 300°C.
Compositions of La-modified lead zirconate titanate ceramics (PLZT, % La: 0, 0.03, 0.12, 0.20) ne... more Compositions of La-modified lead zirconate titanate ceramics (PLZT, % La: 0, 0.03, 0.12, 0.20) near the morphotropic boundary phase (MPB) have been prepared using the hydrothermal process. Characterizations using x-ray diffraction (XRD) and scanning electron microscopy (SEM) have shown that the raw powders present a crystalline structure and exhibit a mixed phase - tetragonal and rhombohedral phases - under heating, and that these powders consist in small particles. Besides, Ladoping have led to a lowering of the temperature of the maximum of the dielectric constant and to an increase of this maximum.
Les poudres ceramiques de titanate de plomb, dopees au lanthane La (PLT), et / ou au fer Fe (PFxT... more Les poudres ceramiques de titanate de plomb, dopees au lanthane La (PLT), et / ou au fer Fe (PFxT ou PLyFxT), de structure perovskite, ont ete preparees par voie sol-gel en adoptant le mode de la destabilisation de solution colloidale (DSC). L'effet de la temperature sur les echantillons a ete etudie par spectroscopie infrarouge a transformee de Fourier (IRTF). L'effet du dopage en La ou Fe sur la structure cristalline a ete examine par diffraction des rayons X (DRX) et par spectroscopie Raman. Nous avons choisi d'effectuer les mesures dielectriques sur trois echantillons pour voir l'effet d'un faible dopage en fer et d'un fort dopage en lanthane sur les proprietes dielectriques des materiaux PbTiO 3 .
La-modified lead zirconate titanate ( PZT) ceramics have been prepared using the hydrothermal pro... more La-modified lead zirconate titanate ( PZT) ceramics have been prepared using the hydrothermal process. Temperature effect on PLZT powders has been studied using TGA-TDA technics, Fourier Transform Infrared (FTIR) spectroscopy, and X-Ray Diffraction (XRD).Dielectric measurements have also been performed. Crystallization temperature has been found to be inferior to that reported in the literature, relative to analogous compounds prepared using other methods. All the obtained results have been discussed and compared to those reported in the literature.
As a lead-free ceramic, lanthanum-modified barium titanate (BLT) has attracted significant attent... more As a lead-free ceramic, lanthanum-modified barium titanate (BLT) has attracted significant attention among researchers in recent years due to its interesting ferroelectric and piezoelectric properties and insulating behavior, which can be improved by the doping effect. For that, (Ba0.7La0.3) (Ti1−xNix)O3 (where x = 0%, 1%, 3%, 5%, 7% or 10%), denoted as BLTNx, were synthesized via the sol-gel process. The effect of the divalent ion Ni2+ on the structural, microstructural and dielectric properties was investigated by x-ray diffraction (XRD) and Fourier transform infrared (FTIR), Raman, and impedance spectroscopy (IS). Surface morphology analysis is done by scanning electronic microscopy (SEM). Dielectric properties were determined in the ranges 28°C to 400°C and 1 kHz to 2 MHz. The results showed that a low doping amount of Ni (x < 5%) increases the dielectric constant. The sample with x = 5% exhibited, at 400°C, a relatively high dielectric constant (ɛ′ = 2202), the sample with x = 3% exhibited, at 100°C, low dielectric loss (tan(δ) = 0.009), and high insulating character, indicating a suitable material for multilayer ceramic capacitors (MLCCs) and energy storage.
In this paper, composite ceramics (1-x)CaCu3Ti4O12–(x)PbZr0.48Ti0.52O3 (with x =0.00, 0.50 and ... more In this paper, composite ceramics (1-x)CaCu3Ti4O12–(x)PbZr0.48Ti0.52O3 (with x =0.00, 0.50 and 1.00), denoted CCTO-PZT, were prepared by a three-stages modified method, in order to achieve high dielectric constant and low loss. Structural investigations carried out by X-ray diffraction (XRD), and FT-IR spectroscopy showed the formation of pure cubic and tetragonal phases for x = 0.00 and x=1.00 compositions, respectively. XRD showed the coexistence of both phases in the CCTO-PZT composite. The morphology of the ceramics was examined by scanning electron micrograph (SEM), results reveal a homogeneous microstructure with two types of grains corresponding to PZT (smaller grains) and CCTO (large grains). Dielectric measurements carried out by an impedance analyzer; show that the dielectric constant of the CCTO-PZT composite is higher than the pure samples (CCTO and PZT) one. The temperature dependence of the ac conductivity indicated that the conduction follows the Arrhenius law and t...
Structural and microstructural properties of sol gel processed BS x T (x = 0.0, 0.05) ceramics ha... more Structural and microstructural properties of sol gel processed BS x T (x = 0.0, 0.05) ceramics have been investigated. Dielectric properties of these ceramics have also been studied as functions of frequency [1kHz-2MHz] at different measurement temperatures (30-200° C). Heat treatment duration effect on dielectric properties and structural ones has been investigated. The results show that heat treatment and its duration has significant effects on structural, dielectric properties and the average grain size of the samples. Scanning electron microscopy (SEM) analysis show quite regular morphology of the grains and an average grain size which decreases with introduction of Sr, in agreement with structural characterization. Raman analysis has given results which are in accordance of XRD and SEM characterizations. Moreover, the permittivity variations as functions of the frequency, show a decrease in the interval [1kHz-100kHz], followed by an anormal increase in the interval [100kHz-1MHz].
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