Structure Of PZT Research Articles

Experimental Band Structure of Pb(Zr,Ti)O3 : Mechanism of Ferroelectric Stabilization.

Pb(Zr,Ti)O3 (PZT) is the most common ferroelectric (FE) material widely used in solid-state technology. Despite intense studies of PZT over decades, its intrinsic band structure, electron energy depending on 3D momentum k, is still unknown. Here, Pb(Zr0.2 Ti0.8 )O3 using soft-X-ray angle-resolved photoelectron spectroscopy (ARPES) is explored. The enhanced photoelectron escape depth in this photon energy range allows sharp intrinsic definition of the out-of-plane momentum k and thereby of the full 3D band structure. Furthermore, the problem of sample charging due to the inherently insulating nature of PZT is solved by using thin-film PZT samples, where a thickness-induced self-doping results in their heavy doping. For the first time, the soft-X-ray ARPES experiments deliver the intrinsic 3D band structure of PZT as well as the FE-polarization dependent electrostatic potential profile across the PZT film deposited on SrTiO3 and Lax SrMn1- x O3 substrates. The negative charges near the surface, required to stabilize the FE state pointing away from the sample (P+), are identified as oxygen vacancies creating localized in-gap states below the Fermi energy. For the opposite polarization state (P-), the positive charges near the surface are identified as cation vacancies resulting from non-ideal stoichiometry of the PZT film as deduced from quantitative XPS measurements.

PbO.ZrO2.TiO2 ve SrO.ZrO2.TiO2 Nanofiberlerin Elektrospinning Yöntemi ile Hazırlanması ve Karakterizasyonu

Lead zirconate titanate (PZT)-based ferroelectric ceramic materials are piezoelectric materials of commercial importance. Strontium zirconate titanate (SZT) perovskite materials also have a wide application area. PZ and SZT starting solutions can be prepared using a variety of suitable methods. Among these methods, the sol-gel process has attracted special attention due to the low temperature requirement, homogeneity and the ability to obtain the appropriate particle size. The electrospinning method is the most effective and widely used method in nanofiber production. Electro-spinning is a method that enables the production of solid and hollow nanofibers in long lengths, homogeneous diameters and various compositions. When the electro-spinning technology is combined with the sol-gel method, continuous nanofibers, nanotubes and filled nanofibers are produced from polymer or ceramic solution under a certain electric field. In this study, lead zirconate titanate (PZT) and strontium zirconate titanate (SZT) solutions containing Sr and Pb were prepared by sol-gel method. Solutions were prepared using metal salts and alkoxides as the precursor materials. The solutions obtained were fed at flow rates of 1.6, 1.8, 2.0 mL / hour and PZT and SZT nanofibers were formed by electrospinning method at 20 kV voltage rating. Different parameters of the electrospinning device were examined and the SZT and PZT nanofibers were produced with optimum properties. Crystal structure, characterization of morphological surface and chemical properties of the produced nanofibers were done with XRD, SEM and EDX, respectively. XRD results showed that the perovskite structure of PZT and SZT was not damaged during Sol-gel and electrospinning processes. A small amount of beady structure was observed in SEM analysis of PZT and SZT nanofibers. According to EDX analysis of nanofibers, it was observed that the PZT and SZT structure was also formed.

Local Structure Analysis around Ti in Lead Zirconate Titanate by X‐Ray Fluorescence Holography

To clarify the mechanism of ferroelectricity in lead zirconate titanate (PZT), the local structure around Ti in a Pb(Zr0.7Ti0.3)O3 single crystal is investigated using X‐ray fluorescence holography. The raw hologram data are contaminated by periodic noise due to the fluctuation of the incident X‐ray intensity. The periodical noise is successfully removed using an inverse Fourier transformation method. From the filtered holograms, the atomic images around Ti can be reconstructed clearly. The reconstructions of B‐site cations demonstrate an outward displacement of the neighboring Ti from the ideal B‐site position, indicating an expansion of the local lattice around Ti. In addition, the splitting of Pb images is found, and the relative displacement between Ti and Pb atoms is deduced. These results contribute to the understanding of the local structure of PZT and can reveal the microscopic origins of very high dielectric and piezoelectric responses, which are essential for designing new and improved ferroelectric materials.

Direct Magnetoelectric Effect in a Sandwich Structure of PZT and Magnetostrictive Amorphous Microwires.

The magnetoelectric (ME) response in a trilayer structure consisting of magnetostrictive Fe77.5B15Si17.5 amorphous microwires between two piezoelectric PZT (PbZr0.53Ti0.47O3) layers was investigated. Soft magnetic properties of wires make it possible to operate under weak bias magnetic fields below 400 A/m. Enhanced ME voltage coefficients were found when the microwires were excited by ac magnetic field of a frequency of 50–60 kHz, which corresponded to the frequency of electromechanical resonance. The as-prepared microwires were in a glass coat creating a large thermoelastic stress and forming a uniaxial magnetic anisotropy. The effect of glass-coat removal and wire annealing on ME coupling was investigated. The glass coat not only affects the wire magnetic structure but also prevents the interfacial bonding between the electric and magnetic subsystems. However, after its removal, the ME coefficient increased slightly less than 10%. Refining the micromagnetic structure and increasing the magnetostriction by stress release during wire annealing (before or after glass removal) strongly increases the ME response up to 100 mV/(cm × Oe) and reduces the characteristic DC magnetic field down to 240 A/m. Although the achieved ME coefficient is smaller than reported values for multilayered films with layers of PZT and soft magnetic alloys as Metglass, the proposed system is promising considering a small volume proportion of microwires.

PZT\u2013NZF/CF ferrite flexible thick films: Structural, dielectric, ferroelectric, and magnetic characterization

The preparation and properties of thick flexible three-phase composite films based on lead zirconium titanate (PZT) and various ferrites (nickel zinc ferrite (NZF) and cobalt ferrite (CF)) were reported in this study. Properties of three-phase composite films were compared with pure polyvinylidene fluoride (PVDF) and PZT–PVDF films. X-ray diffraction data indicated the formation of well crystallized structure of PZT and NZF/CF phases, without the presence of undesirable phases. Scanning electron micrographs showed that the ceramic particles were dispersed homogeneously in the PVDF matrix and atomic force microscopy confirmed that the size of the particles is around 30 nm. Non-saturated hysteresis loops were evident in all samples due to the presence of highly conductive ferrite phases. Under magnetic field of 10 kOe, composite films exhibited a typical ferromagnetic response. Dielectric properties were investigated in the temperature range from −128 to 250 °C and frequency range of 400 Hz–1 MHz. The results showed that the value of dielectric constant of the PVDF/PZT/ferrite composites increased about 25% above the one obtained for pure PVDF.

Photoluminescence spectroscopy of Eu3+: an economical technique for the detection of crystal phase transformation in PbZr053Ti047O3 ceramics

Europium doped Pb(Zr1-xTix)O3(PZT:Eu3+) ceramics at different sintering temperatures have been synthesized and a photoluminescence study has been done. The crystal structure of PZT:Eu3+ is seen to transform from tetragonal to rhombohedral phase at the morphotrophic phase boundary (MPB) as the sintering temperature of the sample increases above 1200 °C. This crystal phase change has also been reflected in the photoluminescence emission spectra in terms of emission peak position and intensity variation. The change in emission pattern is discussed on the basis of magnetic dipole and electric dipole transitions, and a correlation is observed with Raman measurements. The dielectric and piezoelectric measurements have also been done, and the results are compared with the emission studies. Based on the correlation, it is suggested that the photoluminescence of Eu3+ could be an economically reliable probing technique over other phase probe methods near the morphotrophic phase boundary to detect crystal phases.

Effect of IrO2/Pt, IrO2, and Pt bottom electrodes on the structure and electrical properties of PZT based piezoelectric microelectromechanical system devices

In piezoelectric microelectromechanical system devices with PbZr x Ti1−xO3 as the ferroelectric, the bottom electrode can provide a template for oriented PbZr x Ti1−xO3 growth. IrO2/Pt, IrO2, and Pt bottom electrode layers were sputter deposited onto TiO2 and were used as growth templates for oriented PbZr0.52Ti0.48O3 growth. The IrO2 and Pt were found to be {100}- and {111}-oriented, respectively, by X-ray diffraction. Scanning/transmission electron microscopy results indicate that the bottom electrodes are textured; however, the PbZr0.52Ti0.48O3 layer is partially textured. The impact of the bottom electrode type on the electrical properties is investigated by dielectric, ferroelectric, and piezoelectric measurements on circular capacitors formed on blanket PbZr0.52Ti0.48O3 films and unimorph cantilevers. For devices with PbZr0.52Ti0.48O3 on IrO2/Pt bottom electrodes, values for the dielectric constant of 1103 ± 28, loss tangent of 0.070 ± 0.004, maximum polarization of 0.399 ± 0.003 C/m2 at 38 MV/m, and leakage current of 5.4 ± 5.8 nA at 20 MV/m were obtained. Values of normalized strain of 0.0030 ± 0.0001 at 20 MV/m, and effective piezoelectric coefficient, d31,f, of 100 ± 25 pm/V at 15 MV/m were obtained on cantilever unimorphs with electrode area 16 µm × 123 µm and PZT area 16 µm × 125 µm. These values are comparable to results obtained for PbZr0.52Ti0.48O3 on 100 nm thick Pt-only bottom electrodes.

PZT-nickel ferrite and PZT-cobalt ferrite comparative study: Structural, dielectric, ferroelectric and magnetic properties of composite ceramics

Comparative study of different PZT-based composite materials ((x)PbZr0.52Ti0.48O3 + (1-x)CoFe2O4 and (x)PbZr0.52Ti0.48O3 +(1-x)Ni0.7Zn0.3Fe2O4 (x = 0.8 and 0.9)) is presented in the frame of structural, dielectric, ferroelectric and magnetic properties. PZT and NZF/CF powders were synthesized by auto combustion technique. The composites were synthesized by mixing the appropriate amount of individual phases using conventional sintering. XRD data indicated the formation of well crystallized structure of PZT and NZF/CF, without the presence of undesirable phases. SEM micrographs revealed a uniform grain distribution of both, ferroelectric and ferromagnetic phases. Non-saturated hysteresis loops are evident in all samples due to the existence of non-ferroelectric ferrite phase. All the samples exhibit typical ferromagnetic hysteresis loop, indicating the presence of the order magnetic structure. Dielectric investigations revealed that ferrites are the main source of charge carriers, which must be of electronic origin. The activation energy of effective electrical resistivity is heavily influenced by the ferroelectric phase.

Transfer Methods of PZT Thin Capacitor to Flexible Polymer by Self‐Assembled Monolayers

SUMMARYThis paper describes the fabrication method that a lead zirconate titanate (PZT) thin film capacitor, which is formed on a Si substrate by metal organic decomposition (MOD), can be easily transferred to flexible polymer (polydimenthylsiloxane; PDMS) without additional chemical contamination. The thin film capacitor is composed of sandwich structure of PZT between two metal layers. To embed the capacitor structure in the polymer substrate by dry peel‐off process, three kinds of self‐assembled monolayers (SAMs) were investigated for adhesion or antiadhesion layer between metal, polymer, and Si substrate, respectively. Also, the MOD's annealing process with SAMs for PZT lamination was investigated. As a result, the PZT capacitors of 1 μm thickness with a perovskite structure were successfully transferred and embedded in PDMS substrate. These results will be useful for fabricating MEMS devices and integration technology of electrical device to a polymer substrate such as capacitors in three‐dimensional integration or for flexible electronics.

MoP-36 DRY PEEL-OFF METHOD OF TRANSFER PZT THIN CAPACITOR TO FLEXIBLE POLYMER USING SAMs

This paper describes a new transfer method to realize wearable devices with embedded capacitors providing high permittivities and thinner structures. To miniaturize passive elements, such as capacitor on flexible substrate[1], lead zirconate titanate (PZT) thin films are formed on a Si substrate by MOD (metal organic decomposition) method, then can be easily transferred into a polymer (polydimethylsiloxane, PDMS or polyimide) without any chemical contamination. The thin film capacitor is composed of sandwich structure of PZT between two metal electrodes. To embed the capacitor layers in the polymer substrate, three kinds of self-assembled monolayers (SAMs) are investigated for adhesion or anti-adhesion layer among metal, polymer and Si substrate, respectively. As modifying the MOD's sintering process for PZT layers, thin capacitor in 1-μm-thick with perovskite structure is successfully transferred and embedded in a PDMS substrate.

Analyzing the defect structure of CuO-doped PZT and KNN piezoelectrics from electron paramagnetic resonance.

The defect structure for copper-doped sodium potassium niobate (KNN) ferroelectrics has been analyzed with respect to its defect structure. In particular, the interplay between the mutually compensating dimeric (Cu(Nb)'''-V(O)··) and trimeric (V(O)··-Cu(Nb)'''-V(O)··)· defect complexes with 180° and non-180° domain walls has been analyzed and compared to the effects from (Cu'' - V(O)··)(x)× dipoles in CuO-doped lead zirconate titanate (PZT). Attempts are made to relate the rearrangement of defect complexes to macroscopic electromechanical properties.

Effect of grain size on the phase structure and electrical properties of PZT–PNZN quaternary systems

The quaternary systems 0.74Pb(Zr0.47Ti0.53)O3–0.26Pb[(Ni0.6Zn0.4)1/3Nb2/3]O3(PZT–PNZN) have been prepared using the conventional oxide mixing method in a wide temperature region between 1050 and 1250°C. All specimens present high relative density above 95%, indicating a wide sintering window for this system. Investigation of the microstructure reveals a continuous increase in grain size from 1.07 to 2.77μm when the sintering temperature is increased from 1050 to 1250°C, which obeys the common grain-growth law well. However, unlike compositional component PZN–PZT and PNN–PZT, the phase structure of quaternary PZN–PNZN is not sensitive to the grain size. The specimens with different grain size retain the morphotropic phase boundary (MPB) structure and the size induced phase transition does not appear. Excluding the influence of the phase structure, the size effect plays a dominant role in improving the piezoelectric properties, which facilitates the motion of domain walls due to the decreasing number of grain boundary. The optimum piezoelectric parameters are obtained at 1150°C: d33=307pC/N, kp=0.56.

Model of piezoelectric self powered supply for wearable devices

With the development in a few latter years, of micros electromechanical technology (MEMS), the demand in wearable electronics and in cordless detectors is more and more important. These wearable devices have needed more of autonomy and independence in energy. Materials piezoelectric (often called intelligent materials) can be employed like mechanisms to convert the mechanical energy, due to vibration usually ambient, in energy electric. This one can be stored and used in place of conventional battery which presents certain disadvantages such as lasted limited life as well as congestion.In this article, one presents a power analytical model generated by a smart structure of type PZT that can be used as supply energy for electronic device. This model allows the determination of suitable sizes and vibration levels of piezoelectric material for to generate an optimal energy supply for a mobile phone. Two types of vibration mode have been compared as a function of characteristics and piezoelectric ceramic sizes.

Thermal and dielectric behavior of flexible polycarbonate/lead zirconate titanate composite system

ABSTRACTPolycarbonate (PC)/Lead Zirconate Titanate (PZT) composites were prepared using solution mixing method followed by hot pressing. The volume fraction of PZT particles was varied from 0 to 27.5%. SEM showed good dispersion of PZT in the PC matrix. XRD confirmed the perovskite structure of PZT and amorphous structure of polycarbonate. The dielectric constant of the composites measured at 1 kHz, increased ∼3.5‐fold compared with pure PC. The modified Lichtenecker equation agreed well with the experimental data. There was no dispersion in the dielectric constant of the composites for the frequency range of 1 kHz to 10 MHz. However, at frequencies higher than 10 MHz significant drop in dielectric constant was observed. The dissipation factor of the composites was found below 0.02. However, above 1 MHz, an abrupt increment in the dissipation factor was observed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39913.

Sol-solvothermal synthesis and characterization of fine lead zirconate titanate particles

We present a novel low-temperature sol-solvothermal method to synthesize fine lead zirconate titanate (PZT) particles. This sol-solvothermal method combines the advantages of conventional sol–gel process and the solvothermal method, and isopropyl alcohol (IPA) was used as the solvent. The effects of different parameters including KOH concentration, IPA/(IPA + water) ratio and reaction temperature, on the microstructures of the PZT powder were studied. With increasing KOH concentration and reaction temperature, the crystalline structure of as-synthesized PZT transformed from tetragonal to rhombohedral phase. More IPA added in the solvent can effectively reduce agglomeration of the PZT powder and decrease the crystallization temperature, but impurity phase was also detected at high IPA/(IPA + water) ratio. As a result, the synthesis parameters are optimized, and well-crystallized 700 nm PZT particles were successfully synthesized in 2.0 M KOH and 50 % IPA/(IPA + water) ratio at temperatures as low as 120 °C.

OS0305 第一原理計算によるPZT圧電性向上を目的とした添加元素の探索

Recently, piezoelectric material has a very important potential for its property showing high responsiveness as a MEMS (Micro Electro Mechanical Systems) actuator. In addition, the PZT (Lead Zirconate Titanate) is a piezoelectric material most general. Then, physical property changes greatly from changes in the composition ratio. Therefore, function improvement of PZT is tried widely by additive element. However, as for them, empirical method that requires enormous cost and lacking in quantitatively is mainstream. Thus, the application of the results is difficult. Accordingly, in this research, search of the additive element low-cost and quantitatively from the viewpoint of energy by using a first-principles calculation. In consequence, V and Mn can be substitute to the B site on PZT from the cohesive energy value. Moreover, it was confirmed that the structure of PZT is maintained when added in V, and Mn by tolerance factor. Furthermore, V and Mn are lighter than the Zr, so PZT piezoelectricity can be improved by adding V or Mn.

Phase formation, electrical properties and morphotropic phase boundary of 0.95Pb(ZrxTi1−x)O3–0.05Pb(Mn1/3Nb2/3)O3 ceramics

Ferroelectric ceramics in specific composition of 0.95Pb(ZrxTi1−x)O3–0.05Pb(Mn1/3Nb2/3)O3 or PZT–PMnN (with x=0.46, 0.48, 0.50, 0.52, and 0.54) have been investigated in order to identify the morphotropic phase boundary (MPB) composition. The effects of Zr/Ti ratio on phase formation, dielectric and ferroelectric properties of the specimens have also been investigated and discussed. X-ray diffraction patterns indicate that the MPB of the tetragonal and rhombohedral phase lies in x=0.52. The crystal structure of PZT–PMnN appeared to change gradually from tetragonal to rhombohedral phase with increasing Zr content. The dielectric and ferroelectric properties measurements also show a maximum value (εr, tanδ and Pr) at Zr/Ti=52/48, while the transition temperature decreases with increasing Zr content.

Novel Piezoelectric Tactile Sensor Materials with Improved Properties

Lead Zirconium Titanate (PZT) is an example of a piezoelectric material, which can be polarized by an electric field or mechanical stress. This study aims to establish how doping PZT with Strontium will result in PSZT thin films with improved piezoelectric properties for biomedical tactile sensor applications. Various thin film samples were fabricated via sol-gel & spin-coating processing methods-PZT (4 layers), PSZT (4 layers), PSZT-PZT (2L PSZT base-2L PZT) and PZT-PSZT (2L PZT base-2L PSZT), analyzed by X-Ray Diffraction (XRD) and Atomic Force Microscopy (AFM) to determine crystalline structure and surface morphology, and by a ferroelectric analyzer to determine leakage current characteristics and ferroelectric parameters such as Pmax, Prand Vc(representation of piezoelectric properties). The addition of Strontium retains the perovskite structure of PZT and marginally influences the ferroelectric properties. Among the hybrid films, PZT(base)-PSZT showed better ferroelectric characteristics (higher Pmaxand Prvalues). A mathematical relationship between the ferroelectric parameters (Prand Vc) to evaluate the films quality factor in relation to their application as tactile sensors, was also established, from which it was concluded that PZT-PSZT performs much better than the other 3 films for such applications despite high Vcvalues. The improved performance of hybrids may be due to the evolved microstructure and crystalline structure. Present investigation resulted in two important conclusions: PZT-PSZT hybrid films are ideal for tactile sensor applications, and the mathematical relationship developed can be used to evaluate any piezoelectric/ferroelectric materials.

Effects BNT compound incorporated on structure and electrical properties of PZT ceramic

Ferroelectric ceramics with formula Pb(Zr 0.52Ti 0.48)O 3/ x(Bi 0.5Na 0.5)TiO 3 (when x = 0, 0.1, 0.5, 1.0 and 3.0 wt%) were prepared by a solid-state mixed-oxide method and sintered at the temperature between 1050 and 1200 °C for 2 h to obtain dense ceramics. It was found that the optimum sintering temperature was 1200 °C at which all the samples had relative density at least 96% of their theoretical values. Phase analysis using X-ray diffraction showed tetragonal and rhombohedral perovskite structure of PZT with no BNT peak detected, indicating that completed solid solutions occurred for all compositions. Scanning electron micrographs of fractured PZT/BNT ceramics showed equiaxed grain shape with mixed-mode of transgranular and intergranular fractures. Addition of BNT significantly decreased grain size of the PZT ceramic. Measurement of room temperature dielectric constant indicated a gradual increase with increasing BNT content. Results of ferroelectric characterization showed a slight decrease of remanent polarization and coercive field for BNT-added samples, suggesting ceramics which could be easily poled. Good piezoelectric coefficient ( d 33) could be maintained and comparable to that of pure PZT ceramic for the sample with 1.0 wt% BNT addition.

Effect of Fe and Fe–Ba substitution on the piezoelectric and dielectric properties of lead zirconate titanate ceramics

Polycrystalline samples of Fe and Fe–Ba doped lead zirconate titanate (PZT) ceramics near the morphotrophic phase boundary have been synthesized by a solid-state reaction technique. Preliminary X-ray analysis of the compound confirms that there is no change in the crystal structure of PZT on co-doping with Fe and Ba. The maximum mechanical quality factor Q m was found to be 1000 for Fe doped material and 880 for Fe–Ba doped material. The electromechanical coupling factor for Fe and Fe–Ba doped samples were 0.535 and 0.495 respectively. The corresponding values for the piezoelectric charge constant d 33 were 135 and 250 pC/N respectively. These results are discussed in terms of position occupied by dopants in to the lattice and their corresponding microstructures. These Fe–Ba doped PZT materials could be likely candidates for high power ultrasonic and underwater SONAR transducer systems.