Structural and dielectric properties of sol-gel prepared PZT(La, K) ferroelectric ceramics (original) (raw)
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Perovskite Formation and Dielectric Responses in PZN Modified PMF-PZT Ceramics
Journal of Chemistry and Chemical Engineering, 2014
PMF-PZN-PZT (0.01Pb(Mo 1/3 Fe 2/3)O 3-xPb(Zn 1/3 Nb 2/3)O 3-(0.99-x)P(Zr 0.53 Ti 0.47)O 3 piezoelectric ceramics), where x = 0.00, 0.01, 0.03, 0.05 and 0.07 were prepared by a conventional mixed-oxide method. The results show that the pure peroveskit phase forms in these ceramics. X-ray diffraction analysis indicated that the phase of the material is a MPB (morphotropic phase boundary) structure. The effects of PZN content on the crystal structure and electrical properties were investigated. optimal dielectric properties were achieved at composition x = 0.07 ceramics by calcination at 800 °C and sintering at 1,180 °C, with a curie temperature of approximately 430 °C. These results clearly show the significance of PZN in controlling the electrical responses of the PMF-PZN-PZT system.
Structural, dielectric and ferroelectric properties of PLZFNT ceramics
Here we are reporting the structural, dielectric and ferroelectric properties of PLZFNT ceramic having compositional formula Pb 1À1.5x La x Zr 0.588 Ti 0.392 Fe 0.01 Nb 0.01 O 3 (x = 0-0.02 in steps of 0.005). Samples were prepared by solid state route. The structural, dielectric and ferroelectric properties are studied as a function of La content. X-ray diffraction (XRD) analysis reveals pure perovskite tetragonal structure for all the compositions. There is drastic improvement in ferroelectric properties with La substitution. Ratio of remnant to spontaneous polarization (P r /P s ) which indicates the measure of squareness of the PE loop is found to improve with the increase in La content.
Journal of Alloys and Compounds, 2013
The perovskite (ABO 3) Pb 1Àx La x (Zr 0.52 Ti 0.48)O 3 (where, x = 0, 0.05, 0.10) were prepared by a sol-gel route. The X-ray powder diffraction studies of the prepared powders suggest the formation of single-phase PLZT compounds of tetragonal structure. The electrical properties of the prepared ceramics were investigated as a function of both temperature (range 25°C-500°C) and the frequency (range 100 Hz-1 MHz) using complex impedance spectroscopy (CIS). The values of activation energy of the samples were calculated from the slopes of the Arrhenius plots. The remnant polarization (P r) and coercive electric field (E c) were calculated from the ferroelectric loop.
Effect of Er doping on structural and dielectric properties of sol-gel prepared PZT ceramics
Materials Research Bulletin, 1999
The polycrystalline complex compounds of (Pb z Er 1Ϫz)(Zr 0.60 Ti 0.40) 1Ϫz/4 O 3 (z ϭ 0.07, 0.08, 0.10) (PEZT) were synthesized using the metal-alkoxide sol-gel technique. Powder X-ray diffraction (XRD) studies of these compounds suggest that they can be formed in single-phase perovskite structure by a one-step process at a relatively low temperature. Scanning electron microscopy (SEM) analysis shows that the grains are nearly spherical and distributed uniformly in the compounds. Detailed studies of dielectric properties (⑀, tan␦, and) of the compounds as a function of temperature show a broadening of the permittivity peak and a change in transition temperature with the increase of Er 3ϩ concentration. Analysis of the diffusivity (␥) of the peaks in these compounds provides a value between 1 and 2. The higher value of ␥ indicates the greater disordering of the system. The hysteresis loop study confirms the phase transition of the system is of second order.
Perovskite Phase Formation, Phase Transition and Ferroelectric Properties of PZN-based Ceramics
Ceramics solid solutions within the binary system of xPb(Zn 1/3 Nb 2/3 )O 3 − (1-x)Pb(Zr 1/2 Ti 1/2 )O 3 with x = 0.1 -0.5 were synthesized via the mixed oxide method and the columbite method. Phase development of calcined powders and the crystal structure of sintered ceramics were analyzed by X-ray diffraction. Ferroelectric properties were measured to elucidate the phase transformation and identify the impact of the processing conditions. It is shown that there is no significant difference in P r across the composition range. However, the coercive field E c is well dispersed over the compositions. Compared with ceramics prepared by the columbite method, ceramics prepared by the mixed oxide method showed a lower remanent polarization P r and a higher coercive field E c . In addition, both X-ray diffraction and ferroelectric measurements indicated a phase transformation from a tetragonal to a pseudo-cubic rhombohedral phase when the fraction of PZN was increased. The morphotropic phase boundary (MPB) is located between x = 0.2 and 0.3 according to observations made on ceramics prepared with both method.
Journal of Alloys and Compounds
Perovskite Pb1−xLax(Zr0.9Ti0.1)1−x/4O3 dense ceramics (relative density of 93-97%) with compositions across the ferroelectric-antiferroelectric boundary (x = 0.020, 0.030, 0.031, 0.032, 0.033, 0.035, 0.380, 0.040 mol.) were prepared by solid state reaction. The effect of La3+ content on the structural, microstructural characteristics and room temperature functional properties (piezoelectric and dielectric properties) of the PLZT ceramics was studied. The increasing of La3+ doping amount Result in a slight decerase of ceramic grain size from 5 m to 1 m, for the same calcination and sintering parameters. The structural study evidences the formation of perovskite single-phase with rhombohedral to orthorhombic symmetry across the ferroelectric-antiferroelectric boundary. A superposition of both symmetries in the compositional range of (0.025 0.033) is demonstrated by the evolution of relative intensities I(11-1)/I(111) and I(001)/I(100) splitted peaks, characteristic to rhombohedral and...
Journal of Materials Research, 2003
The ternary system of lead nickel niobate Pb(Ni 1/3 Nb 2/3 )O 3 (PNN), lead zinc niobate Pb(Zn 1/3 Nb 2/3 )O 3 (PZN), and lead zirconate titanate Pb(Zr 1/2 Ti 1/2 )O 3 (PZT) was investigated to determine the influence of different solid state processing conditions on dielectric and ferroelectric properties. The ceramic materials were characterized using x-ray diffraction, dielectric measurements, and hysteresis measurements. To stabilize the perovskite phase, the columbite route was utilized with a double crucible technique and excess PbO. The phase-pure perovskite phase of PNN-PZN-PZT ceramics was obtained over a wide compositional range. It was observed that for the ternary system 0.5PNN-(0.5 − x)PZN-xPZT, the change in the transition temperature (T m ) is approximately linear with respect to the PZT content in the range x ס 0 to 0.5. With an increase in x, T m shifts up to high temperatures. Examination of the remanent polarization (P r ) revealed a significant increase with increasing x. In addition, the relative permittivity (⑀ r ) increased as a function of x. The highest permittivities (⑀ r ס 22,000) and the highest remanent polarization (P r ס 25 C/cm 2 ) were recorded for the binary composition 0.5Pb(Ni 1/3 Nb 2/3 )O 3 -0.5Pb(Zr 1/2 Ti 1/2 )O 3 . A l l r i g h t s r e s e r v e d N. Vittayakorn et al.: Perovskite phase formation and ferroelectric properties of the PNN-PZN-PZT ternary system A l l r i g h t s r e s e r v e d N. Vittayakorn et al.: Perovskite phase formation and ferroelectric properties of the PNN-PZN-PZT ternary system A l l r i g h t s r e s e r v e d N. Vittayakorn et al.: Perovskite phase formation and ferroelectric properties of the PNN-PZN-PZT ternary system A l l r i g h t s r e s e r v e d N. Vittayakorn et al.: Perovskite phase formation and ferroelectric properties of the PNN-PZN-PZT ternary system A l l r i g h t s r e s e r v e d N. Vittayakorn et al.: Perovskite phase formation and ferroelectric properties of the PNN-PZN-PZT ternary system A l l r i g h t s r e s e r v e d N. Vittayakorn et al.: Perovskite phase formation and ferroelectric properties of the PNN-PZN-PZT ternary system A l l r i g h t s r e s e r v e d the vicinity of T m . In addition, the hysteresis loops showed that the remanent polarization is nonzero at T m but decays to zero at temperatures above T m . IV. CONCLUSIONS N. Vittayakorn et al.: Perovskite phase formation and ferroelectric properties of the PNN-PZN-PZT ternary system
Dielectric and ferroelectric properties and electric conductivity of sol–gel derived PBZT ceramics
Journal of Alloys and …, 2011
a b s t r a c t (Pb 1−x Ba x )(Zr 1−y Ti y )O 3 (PBZT) is a solid solution in which ferroelectric, relaxor or antiferroelectric properties are observed depending on composition. The substitution of Ba 2+ into A position of the perovskite structure leads to the decrease in phase transition temperature and it gradually leads to relaxor properties. The majority of papers describe PBZT obtained from oxides. We report the results of the investigation of the properties and phase transitions of (Pb 1−x Ba x )(Zr 0.65 Ti 0.35 )O 3 ceramics with x = 0.09, 0.25 and 0.35 obtained by the sol-gel method with final free sintering (FS) at 1573 K/4 h and by the hot pressing (HP) method at 1473 K/2 h/20 MPa. Unlike pure PZT, the properties of HP-PBZT samples obtained at lower (1473 K) temperature are a little inferior than FS samples. It is probably related to the fact that barium requires higher final sintering temperatures.
Dielectric Behavior of PLZT x8020 Ferroelectric Ceramics
Ferroelectrics, 2003
PLZT x/80/20 (x = 6, 8, 10 at%) ferroelectric ceramics were prepared by conventional oxide mixture method. X-ray difraction analysis show pure perovskite phases. The dielectric properties were analyzed in a wide frequency and temperature ranges, specially around the transition temperature, taking into account the incorporation of the lanthanum into the lattice. A relaxor behavior with diffuse phase transition was observed for all compositions.