Structural and electrical properties characterization of (1–x)PbZr0.52Ti0.48O3–xBaFe0.5Nb0.5O3 system (original) (raw)
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Electrical behavior of Pb(Zr0.52Ti0.48)0.5(Fe0.5Nb0.5)0.5O3 ceramics
Materials Chemistry and Physics, 2011
Polycrystalline sample of Pb(Zr 0.52 Ti 0.48 ) 0.5 (Fe 0.5 Nb 0.5 ) 0.5 O 3 (PZTFN) ceramics was prepared by a hightemperature solid-state reaction technique. Preliminary X-ray diffraction analysis confirms the formation of single phase compound with tetragonal crystal structure. The dielectric behavior of the material was studied in a wide frequency (100 Hz-1 MHz) and temperature (30-500 • C) range. The relationship between dielectric constant ε r and temperature showed a single Curie transition temperature (T c = 255 • C), with as large a ε r value as 4200 at T c . A low value of dissipation factor (tan ı), as small as 0.04 up to temperature above than T c (frequency f = 1 kHz), with good insulating properties made the sample for prospective applications in microwave dielectric components and high-power-density capacitors. The higher diffusivity (␥ ∼ 1.6) value of the dielectric peak in the material indicates the greater disordering in the system. The signature of ac conductivity depending upon frequency and temperature exhibits the presence of different type of charge species. It is observed that oxygen vacancy plays an important role for high temperature conduction mechanism and dynamics of polarization of the system.
Processing and Application of Ceramics
In this work, the effects of Ba(Fe0.5Nb0.5)O3 (BFN) addition on the structure and dielectric behaviour of Ba0.06(Na0.5Bi0.5)0.94TiO3 (BNBT) ceramics have been reported. The lead-free (1-x)BNBT-xBFN (where 0 ? x ? 1.0) solid-solutions were synthesized by traditional ceramics fabrication technique and sintered at temperatures up to 1325?C. The X-ray diffraction peaks of the compounds of the entire series were indexed. It is found that the crystal structure of the obtained solid solutions changed from rhombohedral (R3c) to cubic (Pm3m) with an increase in BFN content. The Fourier transformed infrared and Raman spectra also confirmed the formation of solid-solutions. SEMstudies were carried out to evaluate the purity and microstructure of the fabricated ceramics. The dependence of phase transition broadening, phase transition temperature and dielectric parameters with compositional changes were also studied.
Mediterranean Journal of Chemistry
The Ba0.95Bi0.05Ti1-xFexO3 ceramics at (x=0.0, 0.1 and 0.2) were prepared by the solid-state reaction method. The effect of iron substitution on structural and dielectric properties of Ba0.95Bi0.05TiO3 ceramic was studied. These compounds are found to crystallize in only tetragonal phase for x = 0.0 and 0.1 and the mixture of tetragonal and hexagonal phases for x = 0.2. The dielectric properties of Ba0.95Bi0.05Ti1-xFexO3 ceramics at x=0.0, 0.1 and 0.2 of Fe -doping concentration. The dielectric measurements as a function of temperature and frequency are studied and showed two diffuse phase transition and relaxation phenomena. The evolution of dielectric permittivity as a function of the frequency of undoped Ba0.95Bi0.05TiO3 show a relaxation phenomenon for which is displaced to the higher frequencies accompanied by a decrease in dielectric constant when x increase. The Complex impedance Cole-Cole plots showed a negative temperature coefficient of resistivity (NTCR) behavior of the B...
Structure and Dielectric Properties of Lead-Free BaSn 0.1 Ti 0.9 O 3 -BaFe 0.5 Nb 0.5 O 3 Ceramics
Ferroelectrics, 2014
Lead free piezoelectric ceramics (1 À x)BNLT ÀxBZT with x ¼ 0.00, 0.06, 0.09 and 0.12 were prepared using a two-step mixed oxide method. Dielectric, ferroelectric and piezoelectric properties of the ceramics were improved by the addition of the BZT. XRD results show tetragonal symmetry structure of the BNLT-BZT ceramics. It was found that the tetragonality increases with increasing BZT content. The optimum composition is x ¼0.09, where the maximum values of the piezoelectric constant d 33 ( 126pC/N)anddielectricconstant(126 pC/N) and dielectric constant ( 126pC/N)anddielectricconstant(2400) were obtained at room temperature. This BNLT-BZT system can be a promising candidate for lead-free piezoelectric ceramics.
Effect of processing on dielectric properties of (0.95)PbZr0.52Ti0.48O3–(0.05)BiFeO3
Applied Physics A, 2012
An effort has been made to synthesize solid solution of a composition with x = 0.05 in the system (1 − x) PbZr 0.52 Ti 0.48 O 3-(x)BiFeO 3 by the sol-gel method. XRD patterns of the pure PZT and BFO modified PZT samples have shown single phase formation. The effects of substitution of BFO on dielectric properties of PZT have been studied in the frequency range 10 Hz to 100 kHz and temperature range from RT to 773 K. The density was optimized by sintering the BFO modified PZT samples at different temperatures in four batches, S1, S2, S3 and S4. P-E hysteresis loop measurements for all the samples have shown almost saturated polarization. It has been observed that sample S2, sintered at 950°C, exhibits superior dielectric properties of the four samples. The occurrence of weak ferromagnetism, observed in the M-H hysteresis loop, indicates coupling between ferroelectricity and magnetism. Impedance analysis has revealed that all the samples, sintered at different temperatures, have a different grain resistance. A large change in ac conductivity around T c has been observed in all the samples.
Structure–property relations of ferroelectric Pb(Zr0.52Ti0.48)O3–(Bi3.25La0.75)Ti3O12 ceramics
Current Applied Physics, 2008
Ceramics with formula (1 À x)Pb(Zr 0.52 Ti 0.48 )O 3 -x(Bi 3.25 La 0.75 )Ti 3 O 12 (when x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1.0) were prepared by a solid-state mixed-oxide method and sintered at 1150°C for 4 h. All samples had densities at least 95% of theoretical values. Phase analysis using X-ray diffraction indicated the existence of BLT -as well as PZT -based solid solutions with corresponding lattice distortion. Scanning electron micrographs of ceramic surfaces showed a plate-like structure in BLT-rich phase while the typical grain structure was observed for PZT-rich phase. Ferroelectric measurements of these samples showed that addition of small amounts of BLT into PZT increased coercive field and remanent polarization to about 18 kV/cm and 12.5 lC/cm 2 , respectively. Further increasing the amount of BLT in PZT degraded the ferroelectric properties of the ceramics. This behavior was in agreement with their microstructures and dielectric properties.
Solid State Ionics, 2011
Polycrystalline samples of BaFe0.5Nb0.5O3 and (1 − x)Ba(Fe0.5Nb0.5)O3–xSrTiO3 [referred as BFN and BFN–ST respectively] (x = 0.00, 0.15 and 0.20) have been synthesized by a high-temperature solid-state reaction technique. The XRD patterns of the BFN and BFN–ST at room temperature show a monoclinic phase. The microstructure of the ceramics was examined by the scanning electron microscopy (SEM) and shows the polycrystalline nature of the samples with different grain sizes, which are inhomogeneously distributed through the sample surface. Detailed studies of dielectric and impedance properties of the materials in a wide range of frequency (100 Hz–5 MHz) and temperatures (30–270 °C) showed that properties are strongly temperature and frequency dependent. Complex Argand plane plot of ɛ″ against ɛ′, usually called Cole–Cole plots is used to check the polydispersive nature of relaxation phenomena in above mentioned compounds. Relaxation phenomena of non-Debye type have been observed in the BFN and BFN–ST ceramics, as confirmed by the Cole–Cole plots.▶ In this paper we are focused on single-phase BaFe0.5Nb0.5O3 (BFN) and perovskite solid solution ceramics with compositions of 0.85Ba(Fe0.5Nb0.5)O3 + 0.15SrTiO3 (0.85BFN + 0.15ST) and 0.80Ba(Fe0.5Nb0.5)O3 + 0.20SrTiO3 (0.80BFN + 0.20ST) samples. These ceramics were synthesized by the solid-state reaction method. The XRD patterns of the BFN and BFN–ST at room temperature show a monoclinic phase. Detailed studies of dielectric and impedance properties of the materials in a wide range of frequency (100 Hz–5 MHz) and temperatures (30–270 °C) showed that properties are strongly temperature and frequency dependent. Complex Argand plane plot of ɛ″ against ɛ′, usually called Cole–Cole plots is used to check the polydispersive nature of relaxation phenomena in above mentioned compounds. These compounds are very useful for high voltage capacitors and other applications.
Applied Physics A, 2007
Ferroelectric ceramics with formula Pb 0.8 Ba 0.2 [(In 1/2 Nb 1/2 ) 1−x Ti x ]O 3 (PBINT) (x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) were prepared via a two-step solid state reaction method. It was found that ceramics with compositions in the range of x = 0.0 ∼ 0.3 showed a pseudo-cubic structure, whereas the ceramic with x = 0.5 displayed a tetragonal structure. All compositions showed significant frequency dispersion in their dielectric properties. The remanent polarization P r as well as the coercive field E c , measured at room temperature, increases with the Ti content. The experimental results obtained in this system are summarized into a phase diagram, with the morphotropic phase boundary (MPB) located at x = 0.4. Compared with the Pb[(In 1/2 Nb 1/2 ) 1−x Ti x ]O 3 solid solution system, incorporating Ba in the A-site leads to a significant decrease in the dielectric maximum temperature T max , a suppression of the dielectric relaxation parameter γ , and a shift of the MPB composition to a higher Ti content.
Journal of Alloys and Compounds, 2009
Lead-free ceramics based on potassium sodium niobate [(K 0.5 Na 0.5 )NbO 3 ; KNN]-bismuth zinc titanate [Bi(Zn 0.5 Ti 0.5 )O 3 ; BZT] were prepared by the modified-conventional mixed oxide route with normal sintering. The crystal structure and ferroelectric phase transitions were studied by means of X-ray diffraction, thermal and dielectric measurements. The ceramics with perovskite structure were in orthorhombic phase at x ≤ 0.010. When reaching 0.01 < x ≤ 0.03, they became a rhombohedral perovskite structure; and with increasing BZT content, cubic within the studied composition range. The phase Bi 2 Ti 2 O 7 with cubic structure began to appear at x > 0.25 and became dominant while increasing the content of BZT. Furthermore, the phase transition temperature of orthorhombic-tetragonal (T O-T ) and tetragonal-cubic (T C ) decreased when a small amount of BZT was added. As the amount of BZT concentration increased, the structure became denser, and well developed grain morphology with almost no porosity was finally obtained.
Ceramics International, 2018
An investigation was carried out on the surface morphologies, crystal structures and electrical properties of leadfree piezoelectric (1-x)K 0.40 Na 0.60 Nb 0.96 Sb 0.04 O 3-xBi 0.5 K 0.5 HfO 3 ceramics, prepared by conventional solid-state reaction route. Based on X-ray diffraction results and temperature-dependent dielectric properties, we found that the ceramics experienced a structural evolution from orthorhombic phase to multi-phase coexistence and then to rhombohedral phase, with the increase of Bi 0.5 K 0.5 HfO 3 content. Furthermore, a rhombohedral-tetragonal phase boundary was identified at x = 0.035, which was considered to be caused by the merging of rhombohedralorthorhombic and orthorhombic-tetragonal phase transition temperatures. The ceramics exhibited an enhanced piezoelectric activity near the rhombohedral-tetragonal phase boundary, with a piezoelectric constant d 33 of 230 pC/N and a planar electromechanical coupling coefficient k p of 0.340. In addition, a clear composition dependence was observed for the microstructure of the ceramics, which could be explained by the combined effect of vacancies and phase segregations.