Solid Solution Pb Research Articles

T − E phase diagrams and electrocaloric effect in PNN-PT solid solutions

Using the sixth-order free energy expansion of the Landay thermodynamic potential, T − E phase diagrams and the electrocaloric effect (ECE) in solid solutions (1-x)Pb(Ni1∕3Nb2∕3)O3-xPbTiO3 (PNN-PT) were studied under an electric field along the crystallographic directions [001], [101] and [111]. The composition of the samples, temperature range, as well as magnitude and direction of the electric field significantly affect the sequence of phase transitions, stability of various crystalline phases and electrocaloric properties. Direct measurements of the intensive ECE in the 0.8PNN-0.2PT compound were carried out by the method of adiabatic calorimetry at electric field strength E = 6 kV/cm. The large electrocaloric coefficient ΔT∕ΔE = 10 μK ⋅ cm/kV indicates that this compound and other PNN-PT solutions are promising for application as solid-state refrigerants.

Thermophysical properties of solid solutions of lead zirconate titanate obtained in various solid state states

Phase transitions in PbZrO3 (PZ), PbTiO3 (PT), and solid solutions of Pb(Zr1-xTix)O3 system were studied by dilatometric method. The temperature dependence of thermal expansion and linear coefficient of thermal expansion for both single crystals and ceramic samples exhibit several anomalies corresponding to phase transitions of different origin and correlate to the results of X-ray diffraction studies. The obtained results should be taken into account for development of materials and devices based on the studied solid solutions of Pb(Zr1-xTix)O3 system.

Physical properties and structure of mechanically activated solid solution Pb(Zr0.7Ti0.3)O3

Physical properties and structure of mechanically activated solid solution Pb(Zr0.7Ti0.3)O3

Investigation on diffuse phase transition through Raman and dielectric properties of Pb(Fe0.5Nb0.5)O3 – Pb(Co0.33Nb0.67)O3 solid solutions

We report a series of Pb based multiferroic solid solutions (1-x) Pb(Fe0.5Nb0.5)O3 – (x) Pb(Co0.33Nb0.67)O3 (0.1 ≤ x ≤ 0.5) (shortened as PFCN), synthesized using a single-step solid-state reaction method. The structural, microstructural, Raman, and temperature (301–481 K) dependent dielectric (102–106 Hz) and conductivity properties were thoroughly investigated. The room temperature X-ray diffraction data reveals the monoclinic phase with the Cm space group for all the solid solutions. The atomic-level structural parameters were obtained for all the solid solutions from the Rietveld refinement technique, and it was observed that an increase in the unit cell volume with an increase of PCN content in PFN. The field emission scanning electron microscope images confirm the densely packed, uniform coarse arrangement in all the samples. In x = 0.4 and 0.5, a small amount of porous structure was noticed, indicates the reduction in the densities. Energy-dispersive X-ray spectroscopy reveals the existence of Pb, Fe, Co, Nb, and O elements according to stoichiometry. The temperature-dependent Raman spectra of all the solid solutions show a decrease in the intensity and changes in the spectral line shape of B-localized F1u (~250 cm−1) and BO6 octahedral rotation F1g (~260 cm−1) modes around the characteristic temperature, may be a structural transformation from monoclinic to cubic above Tm. The frequency-dependent ε′ and tanδ reveal the presence of Maxwell-Wagner polarization in the lower frequency. The temperature-dependent ε′ shows the ferroelectric relaxor type diffused phase transition Tm (TC) around ~360 K, ~340 K, ~330 K & ~320 K for x = 0.1, 0.2, 0.3 and 0.4, respectively. The reported Tm (TC) systematically decreases with increasing x due to the lower Tm (TC) of PCN compared to PFN. These results were consistent with the anomalies observed at the vicinity of Tm in the Raman spectra. The frequency-dependent ac-conductivity studies reveal the negative temperature coefficient of resistance behavior and obey Johnscher's power law. For x = 0.1 to 0.4, the hump-like behavior was found in both temperature-dependent tanδ and ac conductivity around the transition temperature related to the reorientation of domains, domain wall motion, dipolar contribution to the ferroelectric materials.

Influence of YTS addition on structural and electrical properties of PZT-based ceramics

Perovskite solid solution (1-x)Pb(Zr0.52Ti0.48)O3-xY(Ta1/2Sb1/2)O3 ceramics (abbreviated as PZT-YTS, where x = 0, 0.01, 0.02, 0.03, 0.04 and 0.05) were synthesized by conventional solid state method. The phase structure, microstructure and corresponding electrical properties were studied. X-ray diffraction and Raman analyses show that tetragonal phase structure was obtained in all ceramics at room temperature. Scanning electron micrographs of the samples show uniform grain distribution and grain growth inhibition with the increase of doping content. The dielectric permittivity, dissipation factor, electromechanical coupling factor, Young modulus, mechanical quality factor, piezoelectric charge constant, actual density and piezoelectric voltage constant, for the ceramics with x = 0.04 were: ?r = 714.9, tan ? = 0.03345, KP = 0.635, Y = 10.528 ? 1010 N/m2, Qm = 622.254, d31 = 74.738 ? 10?12 C/N, ?a = 7.67 g/cm3 and g31 = 10.477 ? 10?3 m?V/N, respectively, which are optimal in comparison to other studied samples.

Effects of Nano-Sized In2O3 on Sintering Behavior and Electrical Properties of 0.28Pb(In1/2Nb1/2)O3-0.40Pb(Mg1/3Nb2/3)O3-0.32PbTiO3 Ceramics

0.28Pb(In1/2Nb1/2)O3-0.40Pb(Mg1/3Nb2/3)O3-0.32PbTiO3 ceramics were synthesized by conventional solid-phase method using nano-sized In2O3. All the sintered 0.28PIN-0.40PMN-0.32PT ceramics have pure perovskite structure with composition locating at rhombohedral side around the morphotropic phase boundary (MPB) region. The 0.28PIN-0.40PMN-0.32PT ceramics belong to displacive driving ferroelectrics with apparent diffused phase transition characteristic. Although the rhombohedral-tetragonal ferroelectric phase transition temperature (TR-T) increases only to ∼120 °C due to the solid solution of Pb(In1/2Nb1/2) (PIN), the 0.28PIN-0.40PMN-0.32PT ceramics present high piezoelectric thermal stability till around the Curie temperature (Tm), which extremely widens the working temperature range and makes the 0.28PIN-0.40PMN-0.32PT ceramics suitable for high-temperature piezoelectric applications.

Influence of cation order on the dielectric properties of (1 – x)Pb(Sc0:5Nb0:5)O3-xPb(Yb0:5Nb0:5)O3 ceramics

Abstract Ceramic lead niobates and their solid solutions (1 – x)Pb(Sc0:5Nb0:5)O3 – xPb(Yb0:5Nb0:5)O3 were synthesized by solid state reactions from oxides. The structure of investigated samples was characterized by X-ray diffraction (XRD). Dielectric studies of the ceramics were performed by means of broadband dielectric spectroscopy at the temperature ranging from 600 K to 140 K. For all ceramic samples a diffuse phase transition as well as relaxor ferroelectric behavior were observed.

Influence of decomposition of oversatured liquid solutions on the structure and microhardness of quickly curing alloys of the Pb–Sn system

The results of studies of the structure and microhardness of foil alloys of the lead–tin system obtained by high-speed cooling from the liquid phase are presented. The foil sample had the following dimensions: length – up to 10 cm, width – up to 1 cm, and thickness – 30–80 microns. Melt cooling rate was not less than 105 K/s. A rapidly cooled foil is chara cterized by a dispersed structure. The size of the discharge of tin and lead does not exceed 5 μm. The specific surface of the interfacial boundaries achieve 1.7 μm–1. Due to supercooling, a microcrystalline structure forms in the foil. The average lengths of chords of random secants on lead and tin grain sections in the Pb–73 at.% Sn alloy foil are 0.8 and 1.8 μm respectively. The texture of (111) lead and (100) tin is formed in the foil of alloys of the lead – tin system under certain conditions. The formation of the structure of lead alloys containing from 20 to 95 at.% tin is due to the occurrence of spinodal decomposition of a supersaturated liquid solution, and, in other alloys, due to decay by the mechanism of formation and growth of nuclei of crystalline phases. The stratification of the liquid solution leads to the formation of areas enriched in lead and tin, which contribute to the formation of crystallization centers that are equally distributed in the volume of the foil. The microhardness of the foil alloys, whose compositions are close to eutectic, is less than the microhardness of massive alloys of the same composition, which is associated with the softening effect of grain boundaries and interphase boundaries. Exposure of these alloys at room temperature causes an increase in microhardness due to a decrease in slippage at the boundaries. The decomposition of supersaturated solid solutions of Pb–5 at.% Sn and Sn–1 at.% Pb alloys leads to a decrease in microhardness due to the weakening of the effect of the solid solution hardening mechanism. The results of the study can be used to create fusible solders, bearing alloys, alloys for cable sheaths with improved physicochemical properties.

Preparation, structure and dielectric studies of solid solutions Pb(Fe1–xInx)2/3W1/3O3

New samples of Pb(Fe1–xInx)2/3W1/3O3 solid solutions were synthesized for the first time by the ceramic technology and detail of X-ray and dielectric studies were carried out. It was established that in the concentration region 0 < x < 0.12 the obtained samples are practically single-phase and represent perovskite solid solutions. The temperature and frequency dependences of the dielectric properties of the obtained solid solutions were firstly studied. It was found that the samples exhibit the characteristics of ferroelectrics-relaxor with pronounced maxima of dielectric permeability at Tm = 175–200 K, the position of which is shifted with increasing frequency towards high temperatures. Substitution of Fe for In in the solid solutions lowers the maximum value of dielectric permeability (from ∼4700 at x = 0 to ∼3700 at x = 0.10) without significantly changing its peak position on the temperature scale.

AFM-tip written normal and anomalous domains in PMN-0.4PT crystals

At present, crystals of the solid solutions Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT) are under intensive investigation due to their excellent piezoelectric characteristics. Studies in domain engineering are of importance for an insight into the contribution from the domain formation and resulting domain-wall density to piezoelectric coefficients. In this work, the fabrication of domains by dc AFM-tip voltages was studied in the tetragonal PMN-0.4PT crystals. Two types of domains were observed, either uniformly polarized along the poling field (the “normal” ones), or, following the commonly accepted term, “anomalous” ones containing a small area with the polarization directed oppositely to the poling field. In this work, for the first time, the correlation between the domain shape and the local piezoelectric hysteresis loops Hω−Utip was found, namely, the larger is the local bias voltage Ub, the higher is the tip voltage Utip at which the anomalous domains appear. This finding relates the observed scatter in the exposure conditions corresponding to the anomalous domains formation, to the nonuniform spatial distribution of the local bias fields. The domain diameter D vs Utip and pulse duration tp were investigated for Utip ≤ 50 V and tp from 10 ms to 10 s. The exposure characteristics are independent of the domain shape. For a given tp, D(Utip) is described by a unified linear function in the whole Utip range. The curves D(tp) follow a power law D∼tpk with the exponent k varying very weakly with Utip. The relaxation kinetics of anomalous domains depends on the writing conditions. The normal domains are found to decay significantly faster than the anomalous ones, with the decay kinetics depending on the domain spacing.

Synthesis, structure, dielectric properties and relaxor behavior of a novel solid solution (1-x)Pb(Mg1/3Nb2/3)O3-xBi(Zn2/3Nb1/3)O3

A solid solution of (1-x) Pb(Mg1/3Nb2/3)O3-xBi(Zn2/3Nb1/3)O3 [(1-x)PMN-xBZN)] has been prepared in the form of ceramics with x = 0-0.20 by solid state reaction method. The crystal structure and dielectric properties are investigated. An enhanced relaxor behavior is found when incorporating BZN into canonical relaxor PMN due to the increased chemical disorder. The high temperature slope of dielectric constant as a function of temperature is consistent with the empirical quadratic law. The frequency dependence of the temperature of the dielectric maximum follows the Vogel-Fulcher (V-F) law.

Some Structural Properties of the Mixed Lead–Magnesium Hydroxyapatites

Lead–magnesium hydroxyapatite solid solutions Pb(10–x)Mg x (PO4)6(OH)2 have been prepared via a hydrothermal process. They were characterized by X-ray powder diffraction, Transmission Electron Microscopy (TEM), chemical and IR spectroscopic analyses. The results of the structural refinement indicated that the limits of lead-magnesium solid solutions (x ≤ 1.5), a regular decrease of the lattice constant a and a preferential magnesium distribution in site S(I). Through the progressive replacement of Pb2+ (r = 0.133 nm) by the smaller cation Mg2+ (r = 0.072 nm), all interatomic distances decrease in accordance with the decrease of the cell parameters. According to what could be expected from the coordinance of the metallic sites S(I) (hexacoordination) and S(II) (heptacoordination), the small magnesium cation preferentially occupies the four sites S(I). The results of the TEM analysis confirm the presence of magnesium in the starting solution and reveals the decrease in the average size of crystals. The IR spectra show the presence of the absorption bands characteristic for the apatite structure.

Dielectric response near the singular points on the phase diagrams of multicomponent solid solutions based on PMN-PT

ABSTRACTIn this work the dielectric response of ceramic solid solutions Pb(1-x)Bax(Mg1/3Nb2/3)m(Zn1/3Nb2/3)y(Ni1/3Nb2/3)nTizO3 (x = 0–0.15, m = 0.4541, y = 0.0982, n = 0.1477, z = 0.3) were studied. The existence of two types of singular points on the phase diagrams: tricritical point on the x-T phase diagram and the critical point of the “liquid-vapor” type in the E-T phase diagram were found. Last detected for the first time in the ceramic samples of multicomponent solid solutions. It is shown that there is an increase of dielectric (tricritical point) and pyroelectric (critical point) responses near the observed singular points.

Ізоморфні заміщення у системі Pb(8−x)LnxNa2 (PO4)6(2−x/2)O(x/2), де Ln = Tb, Dy, Ho, Tm і Yb

Compounds with apatite structure having the composition M 10 (ZO 4 ) 6 X 2 (where M = Na + , K + , Ca 2+ , Sr 2+ , Ba 2+ , Pb 2+ , Cd 2+ , Y 3+ , La 3+ , REE etc.; Z = Si 4+ , Ge 4+ , P 5+ , V 5+ , As 5+ , S 6+ , Cr 6+ etc.; X = OH – , F – , Cl – , Br – , I – , O 2– , (vacancies) are characterized by various properties. As a result, they are intensively studied and may be used as bioactive, luminescent and laser materials, sensors, solid electrolytes, sorbents, catalysts. In crystal chemistry the apatite formula can be represented as [M(1)] 4 [M(2)] 6 (ZO 4 ) 6 X 2 . M(1) (4f position) is surrounded by nine oxygen atoms, which are the part of ZО 4 tetrahedra. M(2) (6h position) is surrounded by six oxygen atoms being the part of ZО 4 tetrahedra and X atom (position 2a) located in the structure channel. Cations in the position M(2) form triangles, their central axis coinciding with axis c. Repeating of this structure along axis c enables the formation of channels, in which X ions can be located and move. Such structure allows to make isomorphous substitution by different atoms in structural units M, Z, and X. The present study represents the results of isomorphous substitution of lead by REE of yttrium subgroup, which was mainly realized in the system Pb (8−x) Tb x Na 2 (PO 4 ) 6  (2−x/2) O (x/2) . Substitution of rare-earth elements (REEs, Ln: Tb, Dy, Ho, Tm, and Yb) for lead in the lacunary apatite Pb (8−x) Ln x Na 2 (PO 4 )6 (2−x/2) O (x/2) (0 ≤ x ≤ 2) in accordance to scheme 2 Pb 2+ +  → 2 Ln 3+ + O 2– has been studied by Xray powder diffraction (including the Rietveld refinement), scanning electron microscopy and FT-IR spectroscopy. Single phase solid solutions Pb (8−x) Ln x Na 2 (PO 4 ) 6  (2−x/2) O (x/2) are formed in the range from х = 0.00 to х = 0.55. By changing the parameters of elementary cells from the composition and the phase-vanishing method the solubility limits xmax of REE decreases with an REE atomic number increasing from 0.55 till 0.12 at 800 °C (xmax = 0.53–0.55 for Tb, xmax = 0.45 for Dy, xmax = 0.38 for Ho, xmax = 0.16–0.18 for Tm, and xmax = 0.12 for Yb) were established. Refinements of X-ray diffraction patterns by the Rietveld method show that substitution lead to Pb(2)—O(1,2,3) and Pb(2)—O(2) atomic distances decreases. This study shows that REE atoms substitute for Pb preferentially at the Pb(2) sites of the apatite structure.

Quantitative Microanalysis of (1-x)Pb(Mg(1/3)Nb(2/3))O3×xPbTiO3 (PMNT) Ferroelectric Ceramics.

Optimized quantitative electron-probe microanalysis was applied for compositional characterization of a ferroelectric ceramic single crystal that was made from the complex perovskite-type solid-solution (1-x)Pb(Mg(1/3)Nb(2/3))O3×xPbTiO3 (PMNT). Cation concentrations were determined with high accuracy and ultimate relative experimental uncertainty of ≤±1%, showing that the average chemical composition of the crystal corresponds to Pb(Mg(1/3)Nb(2/3))(0.67)Ti(0.33)O3 (i.e., x=0.33), which is close to the morphotropic phase boundary composition. Over the PMNT single crystal slight compositional heterogeneity was measured for concentrations of the perovskite B-site cations Ti4+, Mg2+, and Nb5+, with variations up to ±2.3%, whereas the Pb concentration remained uniform within a variation below ±0.5%.

Neutron powder diffraction study of Pb[Zrx(Fe2/3W1/3)1–x]O3 solid solutions

This study presents the structural and magnetic properties of solid solutions Pb[Zrx(Fe2/3W1/3)1−x]O3 (PZFW), with x = 0.35 and 0.60. The focus is on the study of magnetic ordering and the co‐existing electrical dipole moments as a function of temperature. Neutron powder diffraction (NPD) measurements showed that both samples possess a pseudo‐cubic structure. A G‐type antiferromagnetic (AFM) order onsets at around 150 K in PZFW with x = 0.35, accompanied by a broad hump in the magnetization, magnetic peak width determined from the NPD patterns, and thermal expansion versus temperature curve, which indicate a diffusive phase transition. Weak anomalous thermal expansion was assigned to the spontaneous magnetostriction. A susceptibility cusp characteristic to an AFM ordering was observed at 15 K though no evident change was observed in the NPD patterns at 12 K. The magnetic behavior is assigned to different size clusters: with decreasing temperature a larger fraction of the material becomes magnetically ordered. Remnant magnetization was observed in PZFW with x = 0.35 at 2 K. No magnetic reflections were seen in PZFW with x = 0.60 down to 12 K. Magnetometer measurements revealed a weak AFM cusp at 8 K, confirmed by hysteresis loop measurements. The off‐center Pb‐displacements and the oxygen octahedra displacement along the cubic axis with respect to the B‐cations generate an electric dipole moment.

Synthesis, Crystal Structure Refinement, and Electrical Conductivity of Pb(8−x)Na2Smx(VO4)6O(x/2)

Solid solutions of Pb(8−x)Na2Smx(VO4)6O(x/2)were studied using X-ray diffraction analysis including Rietveld refinement and scanning electron microscopy and by measuring their electrical conductivity. Crystal structure of the solid solutions was refined and the solubility region0≤x≤0.2was determined for samarium substitution for lead under the scheme2Pb2++□→2Sm3++O2-. The influence of degree of substitution on the electrical conductivity of solid solutions was established.

Application of a Preisach Hysteresis Model to the Evaluation of PMN-PT Ceramics Properties

Abstract The work presents enhanced, relatively new iterative method for obtaining the classical Preisach distribution from a single, saturated hysteresis loop. As the material for research and analysis, the ceramic solid solution (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (x = 0 to 0.40) was selected. Distributions were obtained for (1-x)PMN-xPT ceramics as a function of PT content, and function of temperature, for a selected composition from the morphotropic phase boundary region. The paper also proposes a mathematical model of the Preisach distribution and the parameters of the distribution were calculated. The typical factors achievable directly from the hysteresis loop with a coefficients determined from the analytical Preisach model were compared.

New solid solution Pb2−xSrxFeV3O11 – Synthesis, homogeneity range and characterization

Abstract A substitutional solid solution Pb 2− x Sr x FeV 3 O 11 with homogeneity range from x > 0 to x 2+ ions incorporated into the crystal lattice of the matrix. Pb 2− x Sr x FeV 3 O 11 melts at temperatures from the range 650–700 ± 5 °C, depending on the composition. With increasing strontium content in the new phase, a slight shift of the recorded IR absorption bands towards higher wave-numbers is observed.

How synthesis parameters influence the quality of lead magnesioniobate PbMg1/3Nb2/3O3

Lead magnesioniobate PbMg1/3Nb2/3O3 (PMN) has been prepared using lead oxide and magnesium niobate. Factors that influence the perovskite/pyrochlore ratio in the PMN structure have been studied. In order for the maximal amount of the perovskite phase to be obtained, synthesis should be carried out at 850–900°C; an excess of MgO (1–5 wt %) does not exert a positive effect. An excess of PbO (5–7 wt %) allows one to obtain a phase that contains 85% PMN, with the perovskite structure. The perovskite lattice is found to be stabilized as a result of cationic substitutions (Yb, Lu) in the Mg-Nb sublattice due to the formation of solid solution Pb(Mg1/3Nb2/3)1 − xYb(Lu)xO3, where 0 ≤ x ≤ 0.9.