Perovskite phase formation and ferroelectric properties of the lead nickel niobate–lead zinc niobate–lead zirconate titanate ternary system

The ternary system of lead nickel niobate Pb(Ni1/3Nb2/3)O3 (PNN), lead zinc niobate Pb(Zn1/3Nb2/3)O3 (PZN), and lead zirconate titanate Pb(Zr1/2Ti1/2)O3 (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 (Tm) is approximately linear with respect to the PZT content in the range x [H11505] 0 to 0.5. With an increase in x, Tm shifts up to high temperatures. Examination of the remanent polarization (Pr) revealed a significant increase with increasing x. In addition, the relative permittivity ([H9280]r) increased as a function of x. The highest permittivities ([H9280]r[H11505] 22,000) and the highest remanent polarization (Pr [H11505] 25 μC/cm2) were recorded for the binary composition 0.5Pb(Ni1/3Nb2/3)O3–0.5Pb(Zr1/2Ti1/2)O3

The morphotropic phase boundary and dielectric properties of the xPb(Zr1/2Ti1/2)O3-(1−x)Pb(Ni1/3Nb2/3)O3 perovskite solid solution

The solid solution between the normal ferroelectricPb(Zr1/2Ti1/2)O3(PZT) and relaxor ferroelectricPb(Ni1/3Nb2/3)O3 (PNN) was synthesized by the columbite method. The phase structure and dielectric properties of xPZT-(1−x)PNN where x=0.4–0.9and the Zr/Ti composition was fixed close to the morphotropic phase boundary (MPB) were investigated. With these data, the ferroelectric phase diagram between PZT and PNN has been established. The relaxor ferroelectric nature of PNN gradually transformed towards a normal ferroelectric state towards the composition 0.7PZT-0.3PNN, in which the permittivity was characterized by a sharp peak and the disappearance of dispersive behavior. X-ray diffraction analysis demonstrated the coexistence of both the rhombohedral and tetragonal phases at the composition 0.8PZT-0.2PNN, a new morphotropic phase boundary within this system. Examination of the dielectric spectra indicates that PZT-PNN exhibits an extremely high relative permittivity near the MPB composition. The permittivity shows a shoulder at the rhombohedral to tetragonal phase transition temperature TRT=195°C, and then a maximum permittivity (36 000 at 10kHz) at the transition temperature Tmax=277°C at the MPB composition. The maximum transition temperature of this system was 326°C at the composition x=0.9 with the relative permittivity of 32 000 at 10kHz

Phase transitions and ferroelectric properties in BiScO3-Bi(Zn1/2Ti1/2)O3-BaTiO3 solid solutions

Ceramics solid solutions within the ternary perovskite system Bi(Zn1/2Ti1/2)O3-BiScO3-BaTiO3 were synthesized via solid-state processing techniques. The crystal structure of sintered ceramics was analyzed by x-ray diffraction. A stable perovskite phase was obtained for all compositions with a BaTiO3 content greater than 50 mol %. Furthermore, a change in symmetry from pseudocubic to tetragonal was observed as the mole fraction of BaTiO3 increased. Dielectric measurements show a dielectric anomaly associated with a phase transformation over the temperature range of 30 °C–210 °C for all compositions. Examination of the polarization hysteresis behavior revealed weakly nonlinear hysteresis loops. With these data, ferroelectric phase diagrams were derived showing the transition between the pseudocubic relaxor behavior to the tetragonal normal ferroelectric behavior. This transition was also correlated with changes in the diffuseness parameter

Dielectric Properties of Bismuth Doped Barium Titanate (BaTiO3) Ceramics

Abstract: The dielectric properties of bismuth doped barium titanate ceramics were investigated. The powders were prepared using the solid-state reaction method. The dielectric properties were characterized by means of LCR meter. XRD clearly revealed only a momophasic perovskite of tetragonal asymmetry for the reference BaTiO 3 , which was established to possess both a-a-and a-c-type 90 o domains. Examination of dielectric constant revealed a significant increase with increasing sintering temperature. Furthermore, sintering temperature has been shown to produce a linear increasing in the density. Nevertheless, an increase in the sintering temperature did not show any evidence of a change in transition temperature. The maximum transition temperature of this system was 135 °C at with the relative permittivity of 3500 at 1 kHz. Above the Curie temperature the relative permittivity follows Curie-Weiss law with Curie constant C = 1.8 x 10 5 o

Structural, Phase Transition and Ferroelectric Properties of Pb(Zr Ti )O -Pb(Co Nb )O Ceramic Synthesized by High-temperature Solid-state Reaction Technique

Abstract: Polycrystalline samples of (1-x)Pb(Zr Ti )O -xPb(Co Nb )O (PZT -PCoN ) with x = 0 -0.5 have been synthesized by high-temperature solid-state reaction technique. X-ray diffractograms of the samples reveal the single phase perovskite structure formation with PbCoN content x#0.5. There is a transformation in crystal structure observed from tetragonal to co-existence of tetragonal and pseudocubic to single pseudo-cubic phase with the increase in PCoN concentration in the basic PZT composition. Ferroelectric hysteresis behaviour was also studied as a function of applied electric field for all the compositions. Square behavior of the ferroelectric loops was found with the increase in PCoN r concentration. The maximum value of remnant polarization P (25.3 mC/cm ) was obtained for the 2 0.5PZT -0.5PCoN ceramic

Phase transitions and ferroelectric properties in BiScO3-Bi(Zn1/2Ti1/2)O3-BaTiO3 solid solutions

Ceramics solid solutions within the ternary perovskite system Bi(Zn1/2Ti1/2)O3-BiScO3-BaTiO3 were synthesized via solid-state processing techniques. The crystal structure of sintered ceramics was analyzed by x-ray diffraction. A stable perovskite phase was obtained for all compositions with a BaTiO3 content greater than 50 mol %. Furthermore, a change in symmetry from pseudocubic to tetragonal was observed as the mole fraction of BaTiO3 increased. Dielectric measurements show a dielectric anomaly associated with a phase transformation over the temperature range of 30 °C–210 °C for all compositions. Examination of the polarization hysteresis behavior revealed weakly nonlinear hysteresis loops. With these data, ferroelectric phase diagrams were derived showing the transition between the pseudocubic relaxor behavior to the tetragonal normal ferroelectric behavior. This transition was also correlated with changes in the diffuseness parameter.The following article is from Journal of Applied Physics 102 (2007): 044103 and may be found at http://dx.doi.org/10.1063/1.2769787.</p

Towards the preparation of organic ferroelectric composites: fabrication of a gamma-glycine-bacterial cellulose composite via cold sintering process

The cold sintering process (CSP) has emerged as a revolutionary technique for low-temperature processing of ceramics and composites, enabling high-density fabrication at low temperatures. In this study, we demonstrated the implementation of CSP in fabricating the γ-glycine (γ-G)-bacterial cellulose (BC) composite and evaluated the effect of sintering temperature and holding time on the microstructure and electrical properties. Our findings revealed that an increase in sintering temperature and holding time leads to grain growth, as the transient solvent (water) facilitates the closely-packed microstructure. Moreover, the addition of BC as a filler into the γ-G matrix leads to a composite with a 10% increase in hardness when BC was uniformly distributed in γ-G. The composite with a relative density of 97% was successfully obtained at 120 °C/24 h, preserving the γ polymorph of glycine without the unwanted transformation commonly observed with traditional sintering. We also reported the dielectric and ferroelectric properties of the γ-G-BC composite, exhibiting a remanent polarization of 0.004 μC/cm2 and a coercive field of 1.201 kV/cm. Our findings suggest that CSP is a promising approach for low-temperature processing and fabrication of ceramics, especially when incorporating structurally sensitive filler such as organic ferroelectric, to achieve high-performance composites

Perovskite phase formation and ferroelectric properties of the lead nickel niobate–lead zinc niobate–lead zirconate titanate ternary system

The ternary system of lead nickel niobate Pb(Ni1/3Nb2/3)O3 (PNN), lead zinc niobate Pb(Zn1/3Nb2/3)O3 (PZN), and lead zirconate titanate Pb(Zr1/2Ti1/2)O3 (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 (Tm) is approximately linear with respect to the PZT content in the range x [H11505] 0 to 0.5. With an increase in x, Tm shifts up to high temperatures. Examination of the remanent polarization (Pr) revealed a significant increase with increasing x. In addition, the relative permittivity ([H9280]r) increased as a function of x. The highest permittivities ([H9280]r[H11505] 22,000) and the highest remanent polarization (Pr [H11505] 25 μC/cm2) were recorded for the binary composition 0.5Pb(Ni1/3Nb2/3)O3–0.5Pb(Zr1/2Ti1/2)O3.This article is from Journal of Materials Research 18 (2003): 2882, doi:10.1557/JMR.2003.0402. Posted with permission.</p