Ferroelectric Ceramic Composites Research Articles

Electrocaloric effect, pyroelectric response and energy storage performance of lanthanum-modified PZT relaxor ferroelectric ceramic

Pb0·85La0·10Zr0·60Ti0·40O3 ferroelectric ceramic system was synthesized via the conventional solid-state reaction sintering route. A systematic study on the pyroelectric response, electrocaloric effect and energy storage properties has been carried out in a wide temperature range, in order to explore its multifunctional features. The obtained results from X-ray diffraction technique, performed at room temperature, revealed the coexistence of two ferroelectric phases governed by the tetragonal (P4mm) and monoclinic (C1m1) symmetries. The pyroelectric behavior of the studied sample has been analyzed by the static method, from the temperature dependence of the pyroelectric current. The electrocaloric response as well as the energy storage performance have been investigated from the ferroelectric hysteresis loops (P−E curves), at 50 kV/cm, covering a wide temperature range. The obtained results revealed a ferroelectric ceramic composition with suitable properties and strong potential to be used in multifunctional electronic devices based on pyroelectric sensors combined with high efficiency energy storage performance and solid-state refrigeration technologies.

Ferroelectric Ceramic Materials Prepared by Nanoparticles in Outdoor Environmental Sculpture Art

With the development and progress of the city, people’s research on outdoor sculpture has gone deeper, and the field of material research has been raised to the field of spiritual culture. Tang Sancai is beautiful in color and wonderful in shape, such that when ceramics are used in outdoor environmental sculpture art, except for its performance, its appearance and tone must also be taken into consideration. Even when ferroelectric ceramics are used in outdoor sculptures, changing their shapes and taking into account their colors can be done invisibly only by passing through an electromagnetic field. Ferroelectric ceramics are generally divided into insulating, dielectric, piezoelectric, magnetic, semiconductor, transparent, and infrared sensor ceramics. This article integrates the manufacturing method of ferroelectric ceramics into outdoor environmental sculpture art. First of all, this article describes the ferroelectric ceramics and outdoor environmental sculptures, explains the method of preparing ferroelectric ceramics from barium titanate nanoparticles, and explains the pyroelectric inverse process of the electric card effect principle of electric ceramic materials, the thermodynamics of Maxwell’s relationship, and the thermodynamics of Landau’s phenomenological theory. The elasticity of the system is calculated, and the preparation of tetragonal barium titanate ferroelectric ceramics prepared by hydrothermal nanoparticles and SBT/Cu ferroelectric ceramic composites prepared by nanoparticle metallurgy is explained. In the plasma discharge mode, the optimal temperature for sintering the composite material is obtained. Then through experiments, research on the preparation and performance of the high dielectric constant BTnf-Ag/PVDF ferroelectric ceramic nanocomposite and its application in environmental sculptures are demonstrated. Compared with the two ancient BTnf/PVDF composite materials, the barium titanate fiber prepared by electrostatic spinning shows that the BTnf-Ag/PVDF composite material has a higher dielectric constant, and the dielectric loss is not too high. The 41.8vol% BTnf-Ag composite material has a dielectric constant of 82.6BTnf/PVDF, but the composite material’s dielectric constant is only 62.4, an increase of 32%. The dielectric loss of the 41.8vol% BTnf-Ag composite material is 0.053, and the dielectric loss constant of the BTnf/PVDF composite material is 0.049; the dielectric loss is reduced by 8% year-on-year. Ferroelectric ceramic composites prepared by adding silver ions have ideal dielectric properties and enhanced energy storage density.

Thermometric sensing performance in Erbium modified SrBi2-xNb2ErxO9 ferroelectric ceramic for optoelectronic devices

Er3+ doped ferroelectric ceramic compositions SrBi2-xNb2ErxO9 (x = 0–5 mol %) are prepared by solid-state reaction method and sintered at 1000 °C. The ceramic's structural, ferroelectric, optical, and thermometric sensor properties have been studied. The XRD analysis confirmed the orthorhombic geometry and the A21am phase group of the ceramic. The FTIR studies revealed the typical modes (602 cm−1 and 802 cm−1) of the Aurivillius phases of bismuth layered structure ferroelectrics (BLSFs). The improved hysteresis loops are traced under the electric field < ± 50 kV/cm, and P-E parameters seem to be affected by the insertion of the Er3+ dopant. In upconversion luminescence (UCL) spectra, two intense green bands at 529 nm and 549 nm and a diminished red peak at 670 nm have been identified, corresponding to a 980 nm exciting wavelength. The increase in the lifetime with changing erbium content indicates the efficient energy transfer in Er3+ ions, which results in non-radiative transition at a higher doping level. The optimum dopant concentration is x = 0.03 and is used to measure the pump power dependence on the UCL emission intensity. This study suggests that the two photons are involved in green and red UC emissions. The maximum sensitivity achieved in SrBi2-xNb2ErxO9 ceramic at x = 0.03 is 0.0086 K−1 at 443 K, ranging between temperatures 303 K–443 K, making it a promising non-contact sensor material.

Structural, Ferroelectric, Dielectric and Piezoelectric Studies of Yttrium Substituted SrBi2Nb2O9 Lead-free Relaxor Ceramics

Ferroelectric ceramic compositions SrBi2–xYxNb2O9 (x = 0.0, 0.2, 0.4, 0.6 and 0.8) were prepared via conventional solid-state route with high density (92-99%) establishing the sintering conditions. X-ray diffraction studies confirmed the orthorhombic structure. The micrographs obtained from scanning electron microscopy showed the presence of well packed and randomly oriented needle-shaped grains with an average grain size of 1.624 μm. FTIR and Raman studies on these samples indicated the growth of single phase perovskite material. From the dielectric studies, the phase transition temperature (T c) of strontium bismuth niobate (SBN) was found to be 430oC, whereas the Tc of yttrium substituted SBN (SBYN) was found to decrease from 400° to 370°C. The transition was diffuse and frequency dependent which is a characteristic behavior of relaxor material. The diffuseness parameter (γ) was computed for all the compositions. P-E loop measurements showed a decrease in the parameters P s, P r and E c in yttrium substituted SBN compared to SBN. Piezoelectric studies in SBN and SBYN estimated k p, d 33, g 33 and Qm values. Cole-Cole plots were obtained from studies on SBN and SBYN at different temperatures in the frequency range 50 Hz to 1 MHz. The activation energy values were computed.

Influence of microstructure on electromechanical properties of nano-crystalline La-Pb(Ni1/3Sb2/3)-PbZrTiO3 ferroelectric ceramics

A ferroelectric ceramic composition, Pb0.98La0.02(Ni1/3Sb2/3)0.05[(Zr0.52Ti0.48)0.995]0.95O3, has been synthesized by columbite precursor method followed by mechanical activation for 10 h (MA-10) using high-energy ball mill. Formation of desired perovskite phase during activation was confirmed from analysis of X-ray diffraction patterns, while powder particle size, in nano-meter range, was revealed from high-resolution transmission electron microscopic (HRTEM) investigations. Samples were sintered between 1170 and 1320 °C, and were investigated for microstructure and its influence on electromechanical properties. Increment in grain size with sintering temperature was noticed. 1220 °C sintering temperature posed denser and uniform microstructure amongst all the temperatures and also showed composition close to morphotropic phase boundary (MPB) of PZT with optimum tetragonality which resulted in better electromechanical properties, suggesting the suitability of this composition for power harvesting applications. Phase transition studies revealed normal ferroelectric behaviour with transition temperature of 286 °C.

Influence of Cd doping on the electro-strain of barium zirconate titanate ceramics

Cadmium doped barium zirconate titanate (Ba1−xCdx)(Zr0.13Ti0.87)O3 (BCDZT) ferroelectric ceramic compositions with x=0, 0.02, 0.04 and 0.06 have been prepared by solid state reaction method. X-ray diffraction studies reveal a pseudocubic structure. For increasing Cd content, the bulk ceramic micro-structure reveals an increasing grain size and density. Variations in the dielectric, piezoelectric and unipolar electric field induced strain characteristics are discussed. Increasing Cd content reduces the coercive field, increases the remnant polarization and does not affect the ferroelectric-paraelectric phase transition temperature (~60°C). An optimum Cd content x=0.06 produces highly resistive ceramics with low dielectric loss (tanδ=0.019), and a maximum value of piezoelectric charge constant d33=114 pC/N and unipolar electro-strain of ~0.07%.

Harvesting Power Through Random Vibrations of Aerospace Vehicles from Nanostructured La-Pb(Ni1/3Sb2/3) - PbZrTiO3 Ferroelectric Ceramics

Synthesis by mechanochemical activation route and optimisation for power harvesting properties of nano-structured Pb0.98La0.02(NiSb)0.05[(Zr0.52Ti0.48)0.995]0.95O3 [La-PNS-PZT] ferroelectric ceramic composition has been carried out and reported here for the first time. Progressive perovskite phase formation during mechanical activation from 5 h to 40 h followed by reactive sintering was analyzed from X-Ray Diffraction analysis. Noticeable formation of perovskite phase after10 h of milling and further its completion in successive reactive sintering was observed. Particle morphology of the 10 h activated nano-La-PNS-PZT powder analysed by High Resolution Transmission Electron Microscope (HRTEM) indicated average particle size (d50) of about 24nm. Microstructural studies of samples reactively sintered at 1220 °C were performed by Field Emission Scanning Electron Microscopy (FESEM) for powders activated for various durations, indicated the compact microstructure for 10 h activation which resulted in optimum piezoelectric properties viz. piezoelectric charge coefficient (d33=449x10-12 C/N), piezoelectric voltage coefficient (g33= 32x10-3 m-V/N), Figure of merit for power harvesting (14.4 x10-12 V-m-C/N2) accompanied by excellent stability of permittivity in the range -50 °C to 100 °C. The output voltage obtained from simulated random vibrations of aerospace vehicles at various Power Spectrum Density (PSD) values, measures about 3.0 mV output across resistance of 1 kΩ indicating suitability of composition for harvesting the power from aerospace vehicle vibrations.

Relationship between ferroelectric properties and local structure of Pb1−xBaxZr0.40Ti0.60O3 ceramic materials studied by X-ray absorption and Raman spectroscopies

This paper reports on the structural characterization of Pb1−xBaxZr0.40Ti0.60O3 (PBZT) ferroelectric ceramic compositions prepared by the conventional solid state reaction method. X-ray absorption spectroscopy (XAS) and Raman spectroscopy were used in the probing of the local structure of PBZT samples that exhibit a normal or relaxor ferroelectric behavior. They showed a considerable local disorder around Zr and Pb atoms in the samples of tetragonal or cubic long-range order symmetry. The intensity of the E(TO3) mode in the Raman spectra of PBZT relaxor samples remains constant at temperatures lower than Tm, which has proven the stabilization of the correlation process between nanodomains.

Nanoscale mapping of heterogeneity of the polarization reversal in lead-free relaxor-ferroelectric ceramic composites.

Relaxor/ferroelectric ceramic/ceramic composites have shown to be promising in generating large electromechanical strain at moderate electric fields. Nonetheless, the mechanisms of polarization and strain coupling between grains of different nature in the composites remain unclear. To rationalize the coupling mechanisms we performed advanced piezoresponse force microscopy (PFM) studies of 0.92BNT-0.06BT-0.02KNN/0.93BNT-0.07BT (ergodic/non-ergodic relaxor) composites. PFM is able to distinguish grains of different phases by characteristic domain patterns. Polarization switching has been probed locally, on a sub-grain scale. k-Means clustering analysis applied to arrays of local hysteresis loops reveals variations of polarization switching characteristics between the ergodic and non-ergodic relaxor grains. We report a different set of switching parameters for grains in the composites as opposed to the pure phase samples. Our results confirm ceramic/ceramic composites to be a viable approach to tailor the piezoelectric properties and optimize the macroscopic electromechanical characteristics.

Local order of Pb1−xLaxZr0.40Ti0.60O3 ferroelectric ceramic materials probed by X-ray absorption and Raman spectroscopies

Abstract This paper reports on the structural characterization of Pb 1− x La x Zr 0.40 Ti 0.60 O 3 (PLZT) ferroelectric ceramic compositions prepared by the conventional solid state reaction method. X-ray absorption spectroscopy (XAS) and Raman spectroscopy were used to probe the local structure of PLZT samples that exhibits a normal and relaxor ferroelectric behavior. From the Zr K-edge and Pb L III -edge EXAFS spectra, a considerable dissymmetry of Zr and Pb sites was observed in all samples, including those showing a long-range order cubic symmetry and a relaxor behavior. The Raman spectroscopy results confirmed the existence of a local disorder in all PLZT samples through the observation of Raman active vibrational modes. The variation in the intensity of the E (TO 3 ) mode in the PLZT relaxor samples indicates that the process of correlation between nanodomains stabilizes at temperatures lower than T m .

Tailoring Dielectric Properties of Multilayer Composites Using Spark Plasma Sintering

A straightforward and simple way to produce well‐densified ferroelectric ceramic composites with a full control of both architecture and properties using spark plasma sintering (SPS) is proposed. SPS main outcome is indeed to obtain high densification at relatively low temperatures and short treatment times thus limiting interdiffusion in multimaterials. Ferroelectric/dielectric (BST64/MgO/BST64) multilayer ceramic densified at 97% was obtained, with unmodified Curie temperature, a stack dielectric constant reaching 600, and dielectric losses dropping down to 0.5%, at room‐temperature. This result ascertains SPS as a relevant tool for the design of functional materials with tailored properties.

Change in the Dielectric Properties of Normal and Relaxor Ferroelectric Ceramic Composites in BT-PZT and PMN-PZT Systems by an Uniaxial Compressive Stress

Effects of an uniaxial compressive pre-stress on the dielectric properties of normal and relaxor ferroelectric ceramic composites in BT-PZT and PMN-PZT systems are investigated. The dielectric properties are observed under the compressive pre-stress levels up to 15 and 5 MPa for BT-PZT and PMN-PZT, respectively, using a uniaxial compressometer. Both the dielectric constant and the dielectric loss tangent of the BT-PZT ceramics increase significantly with increasing applied stress. Larger changes in the dielectric properties with the applied stress are observed in the PZT-rich compositions. For PMN-PZT ceramics, the dielectric constant of the PZT-rich compositions increases slightly, while that of the PMN-rich compositions decreases with increasing applied stress. On the other hand, changes in the dielectric loss tangent with stress are found to be compositional independent. The experimental results are explained with the domain wall motion and de-aging mechanisms from the application of the compressive pre-stress. More importantly, this study undoubtedly shows that the applied stress significantly influences the dielectric properties of both ceramic composite systems.

Multiscale Modeling Methodology for Layered Composites of Polymer-Ferroelectric Ceramics

A multiscale modeling scheme of electromechanical coupling of ferroelectric ceramic composites is proposed, which is effective for quantitatively analyzing the relationships among variables of micro/meso/macroscopic and structural (sensor or actuator) scales. This is done by developing effective constitutive equations of material at an intermediate scale, which can be used to connect the mechanical and electric variables between the smaller and larger scales. The methodology is exemplified through investigating the behavior of ferroelectric ceramics of PLZT. The key for connection of variables at different scales is through the remnant polarization and strain at the mesocell. This study deals with the connection of macroscopic variables of ceramics with those of polymer layers for developing constitutive equations for the layered composites of sensors. The numerical results agree with the well-known nonlinear butterfly curve of strain versus electrical field. The influence of volume fraction of the ceramic layers and the relative Young’s modulus on the behavior of the composites are discussed here.

Electric‐Field‐Controlled Permittivity Ferroelectric Composition for Microwave LTCC Modules

A low‐temperature cofired ferroelectric ceramic composition for electrically tunable radio frequency devices is introduced. A sintering temperature of 950°C for BaSrTiO3–MgO was obtained following the combined addition of B2O3 and Li2CO3. The effects of these sintering aids on densification, microstructure, and ferroelectric properties were investigated. The permittivity and dissipation factor values were 234 and 0.0010, respectively, measured at 286.3 K, 1 kHz. The electrically tunable ferroelectric structure for microwave measurement was fabricated throughout the tape‐casting process. Measured permittivity was 130 at 26 GHz and tunability &gt;15% (4 V/μm).

Dielectric relaxation behavior in barium stannate titanate ferroelectric ceramics with diffused phase transition

The temperature dependence of dielectric permittivity was investigated for two ferroelectric ceramic compositions in a barium stannate titanate solid solution system. The dielectric relaxation behavior was observed in these ferroelectrics with diffused phase transition. In view of the polar nanoregion, the relationship between relaxor ferroelectric and ferroelectrics with a diffused phase transition was explored. The results suggest that, in barium stannate titanate, the relaxor ferroelectric dielectric behavior is universal in the diffused phase transition region, but it only appears when the experimental frequency is close to the relaxation frequency of polar nanoregion at that temperature.

Anomalous resistivity of sodium-lithium-niobium-tantalum ceramics

The electric resistance R of the samples of a Na0.88Li0.12Nb0.5Ta0.5O3 ferroelectric ceramic composition with the electron conductivity increased by thermal reduction in vacuum exhibit anomalous temperature variation of the posistor type in the temperature region of 350–400°C, where the nonreduced samples exhibit transition to the state with superionic conductivity. The R(T) anomaly was observed during the electrical measurements both in air and in vacuum. The effect depends on the degree of material reduction and the measurement frequency, reaching 4–5 orders of magnitude for the dc measurements in samples with maximum conductivity. It is suggested that the R(T) anomaly is localized in the near-electrode layer and is related to a mutual influence of the electron and ion transport processes.

Electric field induced strain in (pb,la)(ti,zr)O2ferroelectric ceramics near the tetragonal-rhombohedral morphotropic phase boundary

Abstract The electric field induced strain was studied in PLZT ferroelectric ceramic compositions near the tetragonal-rhombohedral phase boundary. The field induced strain was contributed by domain rotation, together with piezoelectric and electrostriction distortion. The electrostrictive nature of the induced strain increases with La content and Zr/Ti ratio, while the piezoelectric nature of the induced strain decreases with La content and Zr/Ti ratio. The domain rotation related strain is maximized at the morpotropic phase boundary (MPB). A longitudinal strain of 0.54% was obtained for a PLZT 5/56/44 ceramic composition under only 15 kv/cm field. The field induced strain was studied in 8/65/35 ceramics with different grain size. The large grain ceramics show larger field induced polarization and strain and more nearly square hysteresis loops than small grain ceramics. Charge controlled remanent strain was studied for 7.5/65/35 hot pressed ceramics. The remanent strainremanent polarization relation is fo...

Small signal characteristics of ferroelectric ceramics at millimeter wavelengths

A method is described for measuring dielectric properties at wavelengths near 1 mm. The particular material tested was a ferroelectric ceramic composition of 73 per cent barium titanate-27 per cent strontium titanate. Material properties were determined from transmission measurements through an interferometer, and the radiation was generated by a magnetic undulator. It was found that there was a marked dispersion in dielectric constant for this material in the range from 50-100 kMc.