Solid Solution Pb Research Articles

Growth and Characterization of Relaxor Ferroelectric Pb(Fe2/3W1/3)O3—PbTiO3 Single Crystals

Single crystals of the complex perovskite solid solution (1-x)Pb(Fe2/3W1/3)O 3 —xPbTiO3 [(1−x)PFW—xPT], with x = 0, 0.07, 0.13, 0.27 and 0.75, have been synthesized by the high temperature solution growth using PbO as flux, and characterized by X-ray diffraction and dielectric measurements. With the increasing amount of PT, the crystal structure at room temperature changes from a pseudo-cubic (x = 0, 0.07 and 0.13) to a tetragonal phase (x ≥ 0.27). The dielectric properties of the crystals exhibit a typical relaxor behaviour for x = 0 to 0.27 with frequency-dependent peak temperature (T m ) satisfying the Vogel-Fulcher law, while the crystals with higher PT-content undergo a first-order transition at the ferroelectric Curie temperature T C .

Magnetic ordering in relaxor ferroelectric (1 − x)Pb(Fe2/3W1/3)O3–xPbTiO3 single crystals

Single crystals of the perovskite solid solution (1 − x)Pb(Fe2/3W1/3)O3–xPbTiO3, with x = 0, 0.07, 0.27, and 0.75, have been synthesized by the high-temperature solution growth using PbO as flux and characterized by x-ray diffraction and dielectric and magnetic measurements. The crystal structure at room temperature changes from a pseudocubic to a tetragonal phase with the PbTiO3 (PT) content increasing to x ⩾ 0.27. As the amount of PT increases, the relaxor ferroelectric behavior of Pb(Fe2/3W1/3)O3 (PFW) is transformed toward a normal ferroelectric state with sharp and nondispersive peaks of dielectric permittivity at TC. Two types of magnetic orderings are observed on the temperature dependence of the magnetization in the crystals with x ⩽ 0.27. This behavior is explained based on the relationships among the magnetic ordering, perovskite structure, composition, and relaxor ferroelectric properties. Furthermore, the macroscopic magnetization of the system was measured under the application of a magnetic field, which demonstrates different magnetic behavior associated with the weakly ferromagnetic, antiferromagnetic, and paramagnetic ordering in the temperature range of 2 to 390 K. Interestingly, the low-temperature ferromagnetism is enhanced by the addition of ferroelectric PT up to x = 0.27.

Synthesis of the ferroelectric solid solution, Pb(Zr1−xTix)O3 on a single substrate using a modified molecular beam epitaxy technique

High-throughput synthesis of the ferroelectric solid solution Pb(Zr1−xTix)O3 (PZT) on single Pt∕Ti∕SiO2∕Si substrates was demonstrated using a modified molecular beam epitaxy (MBE) system. The PZT films exhibited a phase transition from rhombohehdral to tetragonal symmetry as a function of Zr:Ti ratio, across the substrate diagonal. This was consistent with the presence of a morphotropic phase boundary at Zr:Ti ratio of 0.64:0.36, different from the value of 0.53:0.47 observed for bulk ceramics. All points on the films exhibited ferroelectric hysteresis. Results demonstrate the feasibility of high-throughput MBE for deposition of complex ferroelectric oxides, and pave the way for further materials discovery.

Dielectric characters of 0.7Pb(Mg 1/3Nb 2/3)O 3–0.3PbTiO 3 ceramics fabricated at ultra-low temperature by the spark-plasma-sintering method

Solid solution (1 − x)Pb(Mg 1/3Nb 2/3)O 3– xPbTiO 3 shows high dielectric constant near room temperature and is an ideal capacitor material. The composition 0.7Pb(Mg 1/3Nb 2/3)O 3–0.3PbTiO 3, which is located near the morphotropic phase boundary, were densified by the spark-plasma-sintering method at an ultra-low temperature (700 °C). Dielectric constant measurement shows that the thus prepared sample shows higher dielectric constant at room temperature and good temperature stability in a wide temperature range. The behavior is much different from that of samples sintered by conventional method and could be ascribed to size effect.

Picturing the elephant: Giant piezoelectric activity and the monoclinic phases of relaxor-ferroelectric single crystals

Understanding the relationship between the structure and “giant” piezoelectric properties of relaxor ferroelectric solid solutions (1–x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 [PMN–xPT] and (1–x)Pb(Zn1/3Nb2/3)O3–xPbTiO3 [PZN–xPT] is an extremely difficult task. In this article, three main paradigms are reviewed. In the first, the monoclinic phases present at the morphotropic phase boundary (MPB) are responsible for the giant piezoelectric response in that they allow, or at least facilitate, polarization rotation. In the second, a strong polarization rotation effect is explained by the large piezoelectric shear coefficients of zero-field rhombohedral and orthorhombic phases due to the near degeneracy at the MPB and the intrinsic softness of the relaxor state; zero-field monoclinic symmetries are explained by residually distorted rhombohedral and orthorhombic phases in the presence of internal stresses and/or residual bias fields. In the third, the monoclinic “phases” are composed of very finely twinned rhombohedral or tetragonal domains. In this “adaptive phase” model, based on that for ferroelastic martensites, the large electric-field induced strains are extrinsic in nature and result from the progressive switching of the component “nano-twins”; the ease of polarization rotation is explained by a high domain wall mobility. These paradigms remain to be mutually reconciled. The article includes a thorough review of the history of PMN–xPT and PZN–xPT single crystals and, particularly, the most important work done over the last decade.

Synthesis of the Ferroelectric Solid Solution, Pb(Zr1−xTix)O3 on a Single Substrate Using a Modified Molecular Beam Epitaxy Technique

AbstractHigh-throughput synthesis of the ferroelectric solid solution Pb(Zr1−xTix)O3 (PZT) on single Pt/Ti/SiO2/Si substrates was demonstrated using a modified molecular beam epitaxy (MBE) system. The PZT films exhibited a phase transition from rhombohehdral (R) to tetragonal (T) symmetry as a function of Zr:Ti ratio, across the substrate diagonal. This was consistent with the presence of a morphotropic phase boundary (MPB) at a Zr:Ti ratio of 0.64:0.36, different from the value of 0.53:0.47 observed for bulk ceramics. All points on the films exhibited ferroelectric hysteresis loops. The results demonstrate the feasibility of high-throughput MBE for deposition of complex ferroelectric oxides, and pave the way for further materials discovery, in particular Pb-free piezoceramics.

The influence of the Zr/Ti content of the PZT ceramics obtained by sol-gel method on the electric conductivity

In this work, the results of investigations of the PZT ceramics, received on the base of two - component solid solutions Pb(Zr x Ti 1-x )O 3 are presented. The samples were obtained by conventional ceramic sintering method with nanopowders received in the sol-gel method. The temperature dependencies of the electric conductivity σg or all samples, with different content Zr/Ti (0.35 ≤ x ≤ 0.65), in the range temperatures of 300 ÷ 750K, were performed. On the base of the InaT = f(1/T) dependencies, the activation energy E a was calculated. The determined values of the E a were limited in the range 0.53 ÷ 0.71 eV for ferroelectric phase as well as 0.75 ÷ 0.80 eV for paraelectric phase.

Thermal properties of PZT-based ferroelectric ceramics

The thermal properties of piezoelectric ceramics (PKR-8, PKR-7M) based on lead zirconate titanate solid solutions Pb(Ti, Zr)O3 were studied over the temperature range 300–800 K. The thermal conductivity and thermal expansion coefficients were found to exhibit an anomalous behavior in the region of the ferroelectric phase transition.

IMPEDANCE SPECTROSCOPY AND TIME DEPENDENT RELAXATION BEHAVIOR OF CERAMIC ACTUATORS JOINED BY GREEN BODY JOINING

ABSTRACT The solid solution of Pb(Mg,Nb)O3—Pb(Zr,TiO)O3 materials have high piezoelectric constant of 600∼650 pC/N and electromechanical coupling coefficient k p of 0.65. Due to such high piezoelectric constant and electromechanical coupling coefficient, Pb(Mg,Nb)O3—Pb(Zr,TiO)O3 materials have been attracted attentions for the applications of multilayer ceramic actuators. Actuators are fabricated by staking piezoelectric ceramic materials and inner electrodes, alternatively. However, it is extremely difficult to fabricate huge ceramic actuators without any serious problems during the fabrication process, since there are strikingly different shrinkage rate between the ceramic materials and metal electrodes. In this research, new joining method will be proposed for huge ceramic actuators, and then their electrical properties were investigated. Time dependent leakage current density and impedance spectroscopy were employed to expect device performances.

Influence of Ce3+ doping on the structure and luminescence of Er3+-doped transparent glass-ceramics

Abstract Transparent glass-ceramics possess high thermal and mechanical properties, easy shaping allowing fibers elaboration and easy synthesis. However, previously studied Yb:Er-doped glass-ceramics do not appear efficient enough for optical amplification at 1.5 μm in the telecommunication window. So, the addition of Ce 3+ doping ions was performed. Oxyfluoride glasses (GeO 2 –PbO–PbF 2 ) doped with ErF 3 , YbF 3 and CeF 3 were prepared and heated above glass transition temperature to obtain transparent glass-ceramics. Such treatment brings about the precipitation of fluorite-type nanocrystallites embedded into an amorphous oxide phase. Differential Thermal Analysis shows evidence that CeF 3 acts as nucleating agent for the heterogeneous crystallization of the s-PbF 2 phase. Through Transmission Electron Microscopy the morphology of these glass-ceramics was studied. Energy dispersive X-ray microanalysis and unit cell parameter study show a segregation of the three rare-earth ions inside the fluorite crystallites, forming a solid solution Pb 1− x − y − z Er x Yb y Ce z F 2+ x + y + z . The luminescence characteristics of the glass-ceramics doped with ErF 3 , YbF 3 and CeF 3 were compared to those of Yb:Er-doped glass-ceramics. CeF 3 enables to dramatically decrease the up-conversion fluorescence of Er 3+ . The study of temporal dynamic of the 4 I 13/2 level of Er 3+ reveals a cross-relaxation process between Er 3+ and Ce 3+ . Hence, the presence of Ce 3+ enables to decrease the Er 3+ up-conversion fluorescence at the benefit of the fluorescence of interest at 1.5 μm, which is strongly enhanced.

Predominant factors affecting the dielectric and piezoelectric properties of bismuth-containing complex perovskite solid solution

To study the factors affecting the dielectric and piezoelectric properties of bismuth-containing complex perovskites, the solid solution (1− x)Pb(Mg 1/3Nb 2/3)O 3– xBi(Mg 2/3Nb 1/3)O 3 was prepared by the solid state reaction method and its dielectric and piezoelectric properties were investigated. It is found that (1) at room temperature, the nonlinearity of the DE-loop for Pb(Mg 1/3Nb 2/3)O 3 is completely suppressed at a rather low x (<5%); (2) dielectric constant versus temperature curves deviate from the Curie–Weiss law at a temperature T d much higher than the dielectric constant peak temperature T m and T m− T d decreases considerably with increasing x; and (3) frequency dispersion Δ T m= T m (1 MHz)− T m (10 kHz) increases with increasing x. Possible factors responsible for the variation of the dielectric and piezoelectric properties with x are discussed.

Investigation of thermoelectric parameters of solid solutions Pb 1− xSn xTe〈Cd〉 and determination of their applications

A new modified Bridgman method of the growth of volumetric solid solutions of the A 4B 6 compounds is developed. Experimental investigations of thermoelectric parameters of four compositions, grown by the mentioned method, are carried out. The iso-structural transition for all compositions at T≈300 K in the form of sharp peak in the electrical conductivity was observed, its explanation is given. High values of thermal e.m.f. coefficient (400–450 μV/K) have detected for the n-Pb 1− x Sn x Te〈Cd〉 samples. On the basis of experimental data and calculations, it is shown that there is enough wide temperature range, where the mentioned high values kept save. It opens possibilities to use these materials as sensors of thermal radiation. It is shown that due to features of band structure, under certain conditions, it is possible to increase the efficiency of the p-Pb 1− x Sn x Te〈Cd〉 composition up to 4×10 −3 to 6×10 −3 K −1.

Mn substitution in the solid solution series Bi 2Pb 8− x(PO 4) 6O 2− x. The crystal structure of Bi 1.5(Pb 7.3Mn 0.7)(PO 4) 6O 1.3 a member of a new solid solution series Bi 2− xPb 8(PO 4) 6O 2−1.5 x

A single-crystal from a solid solution Bi(Pb 4− x Mn x )P 3O y was selected and its crystal structure determined from 3-dimensional X-ray diffraction data. The crystal is orthorhombic, Pnma, a=12.967(3) Å, b=10.294(2) Å, c=8.9994(18) Å. The 1460 unique reflections were refined by least squares on F 2 to R 1=0.0352. The stoichiometry based on the atomic parameters is Bi 1.5Pb 7.3Mn 0.7(PO 4) 6O 1.3 Z=2. Of the two crystallographically independent PO 4 groups one tetrahedron is regular while the oxygen ions of the other one are disordered, giving rise to two tetrahedral orientations. One of the crystallographic Pb sites contains vacancies that are filled by Mn. The structure is formed by the 3-dimensional articulations of one Bi–6O and three Pb–7O polyhedra and two PO 4 tetrahedra one of which is disordered. In addition to the previously reported solid solution Pb 8− x Bi 2(PO 4) 6O 2− x there exists also a second type of solid solution, Pb 8Bi 2− x (PO 4) 6O 2−1.5 x .

Solid solution Pb 1− xSr xTiO 3 and its thermal expansion

The solid solution limit of Pb 1− x Sr x TiO 3 was determined in the composition range of 0≤ x≤1.0 at room temperature (RT). The phases were isolated and indexed in a tetragonal system with x<0.5 and in a cubic one with x≥0.5. The cell parameters of Pb 1− x Sr x TiO 3 continuously, but nonlinearly, change with solubility x. The intrinsic thermal expansions of the solid solution compounds Pb 1− x Sr x TiO 3 ( x=0, 0.15, 0.20, 0.50, 0.90, 1.0) were obtained in the temperature range from RT to 1173 K with high-temperature X-ray powder diffraction. Negative thermal expansion coefficients of Pb 1− x Sr x TiO 3 ( x=0, 0.15, 0.20) were found below the Curie points. The thermal expansions of these titanate ceramics were highly correlated with the solubility in the solid solution Pb 1− x Sr x TiO 3.

Characterization of PZT thick films fired on LTCC substrates

Ferroelectric ceramic materials based on solid solutions of Pb(Zr,Ti)O3 (PZT) are used in the electronics industry for sensors and actuators and for electromechanical transducers, to name just a few examples. Thick-film technology, i.e., the deposition of thick-film pastes by screen printing, primarily on alumina substrates, is a relatively simple and convenient method to produce layers with a thickness up to 100 μm. The characteristics of thick-film ferroelectrics are similar to those of bulk materials [1–4]. Low-temperature co-fired ceramics (LTCC) materials, which are sintered at the low temperatures typically used for thick-film processing, i.e., around 850 ◦C, are based either on crystallizable glass [5, 6] or a mixture of glass and ceramics, for example, alumina, silica or cordierite (Mg2Al4Si5O18) [7, 8]. Jones et al. have presented a comparison of the mechanical and chemical characteristics of both green and fired LTCC tapes from different suppliers in [9]. Ceramic multi-chip modules (MCM-C) are multilayer substrates with buried conductor lines. An additional contribution to the smaller size and the higher density of MCM-C is the ability to integrate screenprinted resistors, or sometimes capacitors and inductors. These screen-printed components can be placed either beneath the discrete components on the surface of the multilayer dielectric or buried within the multilayer structure. For an overview of passive integrated components in MCM see, for example [10]. For some applications, for example integrated sensors or micro-actuators, PZT thick-films on LTCC that are sintered at relatively low temperatures (around 850 ◦C) comparable with LTCC’s firing temperatures, would be of interest [11, 12]. The aim of this work was to study the compatibility between LTCC and screenprinted PZT as well as the electrical characteristics of the PZT layer. PZT 53/47 powder (PbZr0.53Ti0.47O3) with an excess 6 mol% of PbO was prepared by mixed-oxide synthesis at 900 ◦C for 1 h from high-purity PbO (litharge) 99.9% (Fluka), ZrO2 99% (Tosoh), and TiO2 99% (Fluka). To this was added 2 wt% of lead germanate, with the composition Pb5Ge3O11 (melting point 738 ◦C) as a sintering aid. Lead germanate (PGO) was also prepared by mixed-oxide synthesis from PbO and GeO2 99% (Ventron) at 700 ◦C. After synthesis, both compositions were ball milled in acetone for 1 h and dried. A thick-film paste was prepared from the PZT (2% PGO) and an organic vehicle (ethyl cellulose, alpha-terpineol and butil carbitol acetate) by mixing on a three roll mill. The green LTCC 951 tape (Du Pont) and alumina ceramics were used for substrates. The thick-film structure was prepared by first printing gold film (Remex 3243) and then the PZT film. The PZT film was printed 6 times with intermediate drying. The gold and PZT layers were cofired at 850 ◦C for 8 h in a closed alumina crucible. The thickness of the PZT films after the thermal treatment was around 50 μm. The green and fired Du Pont LTCC 951 tapes were analyzed by X-ray diffraction (XRD) analysis with a Philips PW 1710 X-ray diffractometer using Cu Kα radiation. X-ray spectra were measured from 2 = 20 ◦ to 2 = 70 ◦ in steps of 0.04 ◦. X-ray spectra are shown in Fig. 1. The unfired material is a mixture of alumina and glass. After firing at 850 ◦C peaks of anorthite ((Na,Ca)(Al,Si)4O8) phase appear. The peaks of alumina and anorthite are denoted by “A” and asterisk, respectively. For the electrical measurements gold electrodes were sputtered onto the PZT films. The values of the remanent polarization and the coercive field were determined from ferroelectric hysteresis curves measured with an Aixact TF Analyzer 2000 at 50 Hz. The real and imaginary parts of the complex dielectric constant were measured with an HP 4284 A Precision LCR Meter at 1 kHz. In Table I the electrical parameters, i.e., remanent polarization Pr, coercive field Ec, dielectric constant e′ and dielectric loss tan δ, of the co-fired LTCC/Au/PZT structure are presented. The electrical characteristics of this structure are compared to the characteristics of a similar structure printed on alumina substrates [13]. Hysteresis loops of the PZT films on the alumina and LTCC substrates are shown in Fig. 2.

Properties of PbFe2/3W1/3O3–PbTiO3 System in the Range of Morphotropic Phase Boundary

The solid solution (1-x)Pb(Fe2/3W1/3)O3–xPbTiO3 with x ranging from 0.0 to 1.0 was investigated at T=300 K in order to determine the composition range corresponding to the morphotropic phase boundary. A change from pseudo-cubic to tetragonal symmetry was found with increasing x. The cell parameters depend on the PbTiO3 amount. In the range of compositions from x=0.20 to x=0.37, both pseudo-cubic and tetragonal phases coexist, with different relative amounts. Infrared and Raman experiments confirmed a continuous change in the local ordering of the system. A transition from relaxor to normal ferroelectric behaviour with increasing PbTiO3 addition was shown by the dielectric data.

Structural study of Pb(Fe 2/3W 1/3)O 3–PbTiO 3 system

The crystalline structure of the solid solution (1− x)Pb(Fe 2/3W 1/3)O 3– xPbTiO 3 (PFW–PT) with x=0, 0.2, 0.25, 0.3, 0.35, 0.4 and 1 was analysed using X-ray diffraction (XRD) with comparative cell-refinement methods, in order to detect the change in symmetry with composition. Pure PFW shows pseudo-cubic symmetry for temperatures in the range 85–423 K. For the temperatures T=85 K and T=300 K, the solid solutions have cubic or tetragonal structures. The cell constants are functions of PbTiO 3 amount. A temperature-dependent Morphotropic Phase Boundary (MPB) separating the pseudo-cubic (relaxor) and tetragonal (ferroelectric) phases might be present. The ranges of compositions for this boundary are: x<0.2 at T=85 K and x∈(0.3,0.35) for T=300 K.

Low-temperature property investigation of the lead indium-niobate–lead nickel-niobate solid solution

The complex perovskite solid solution (1−x) Pb(In1/2Nb1/2)O3–(x) Pb(Ni1/3Nb2/3)O3 has been successfully prepared by the Columbite precursor method. The temperature dependencies of the dielectric constant and pyroelectric coefficient were measured between −261 and 200°C. Relaxor ferroelectric behavior has been noticed in all compositions across the solid solution. The room-temperature electrostrictive coefficient, Q33, was 1.83×10−2C2/m4 for x=0.10. No room-temperature piezoelectric activity was detected; however, upon cooling to −261°C the maximum coupling coefficients kp=29%, kt=11%, and k33=31% were observed for the composition x=1.00.

PZN-PT Single-Crystal Thin Film Monomorph Actuator

We report on the use of single-crystal lead zinc niobate-lead titanate films in monomorph actuators. The article responds to the growing interest in solid-solution (1 m x )Pb(Zn 1/3 Nb 2/3 )O 3 - x PbTiO 3 relaxor ferroelectrics based on their large piezoelectric coefficients and their integration into microelectromechanical system. Freestanding films are fabricated by slicing a 7 w m-thick layer off the crystal bulk and assembled into a flexural actuator, thus circumventing polycrystalline deposition techniques. One-micron deflections are observed at 100 V for ∼1 mm-long films. The article discusses the non-uniform electric field distribution profile established in the films and its role in the actuation process.

Thermal Expansion and Polarization Changes at Phase Transitions in the Perovskite Pb[Zr 1−x (Fe 0.5 Nb 0.5 ) x ]O 3 Ceramics

The phase state of solid solutions Pb[Zr 1 m x (Fe 0.5 Nb 0.5 ) x ]O 3 (0<x<0.2) were studied. The anomalies of dielectric properties and thermal expansion at the phase transition from antiferroelectric to ferroelectric and from ferroelectric to paraelectric phases were investigated. The transformation of the type of ferroelectric-paraelectric phase transition from the first order to the second order was established.