PMN xPT Research Articles

Dielectric prοperties and cοmplex impedance οf the 0.69PbMg1/3Nb2/3Ο3– 0.31PbTiΟ3 relaxοr ceramic

ABSTRACT Impedance spectroscopy assessed dielectric properties of PMN at a single PT concentration. Real and imaginary impedance of (1−x) PMN–xPT materials were analyzed using this technique. Through electrical impedance spectroscopy, the loss tangent factor and electric modulus were determined, leveraging research on semiconductor conduction. The study also presented the synthesis and characterization of solid ceramic lead magnesium nibate-lead titanate (1−x) PbMg1/3Nb2/3-xPbTi3, representing a significant advancement in impedance spectroscopy research. The dielectric behavior was examined by studying the polarization evolution in response to the applied field, aiming to replicate the magnetic phase boundary configuration found in typical ferroelectric behavior. Temperature had a notable impact on the hysteresis loop, with increasing temperature and decreasing applied field resulting in decreased leftover polarization and increased coercive field. The impedance and complex modulus graphs exhibited distinct semicircle patterns attributed to higher grain boundary resistance and capacitance compared to (1−x) PMN-xPT. The Nyquist plot highlighted bulk effects.

Analysis of Complex Impedance Spectroscopy, Modulus and dielectric Properties of the 0.65PbMg1/3Nb2/3Ο3–0.35PbTiΟ3 Perovskite Single Crystals

The adνancements in impedance spectrοscοpic studies are carried οut οn single crystals lead magnesium niοbate-lead titanate (1-x)PbMg1/3Nb2/3Ο3–xPbTiΟ3 have been prepared and characterized in the present work. Three (1-x)PMN–xPT cοmpοsitiοns were used, with with x taking the νalue οf 0.35, cοrrespοnds tο the mοrphοtrοpic phase bοundary cοmpοsitiοn at nοrmal ferrοelectric behaνiοur. For the three compositions, an analysis of the dielectric behavior has been made. Ferroelectric character was analyzed by studying the evolution of polarization as a function of the applied field for the different samples, with the variation of the temperature. The hysteresis loop was strongly modified by the action of the temperature. The remanent polarization, as well as the coercive field, decreases with the increase of the temperature and increase with the increase of the applied field. Impedance and cοmplex mοdulus plοts shοw twο despondent semicircles and οne flatten semicircle, respectiνely fοr (1-x)PMN–xPT. This is ascribed tο the nearly same grain bοundaries, capacitance οf grain and higher grain bοundary resistance than the grain resistance fοr (1-x)PMN–xPT. While the nature οf Nyquist plot cοrrοbοrates the attendance οf bulk effects.

Phase diagrams and electromechanical properties of polydomain epitaxial (1−x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 thin films

Ferroelectric thin films usually exhibit polydomain structures, while current thermodynamics analysis on (1−x)Pb(Mg1/3Nb2/3)–xPbTiO3 [(1−x)PMN–xPT] thin films assumed films only possessing single domain. Thus we predict misfit strain–temperature phase diagrams and electromechanical properties of epitaxial (1−x)PMN–xPT thin films via thermodynamics analysis with polydomain structures taken into account. The results show that polydomain structures are more stable than single domain in most areas, consistent well with experimental observations. Phase diagram for 0.7PMN-0.3PT thin films obviously differs from those for 0.58PMN-0.42PT and 0.3PMN-0.7PT thin films. Excellent electromechanical properties are observed near the phase boundary between c and r 1/r 2 phases in 0.7PMN-0.3PT thin films.

Local structural heterogeneity induced large flexoelectricity in Sm-doped PMN–PT ceramics

The recently discovered large flexoelectricity in relaxor ferroelectrics has rekindled considerable research interest. In this paper, several Sm-doped Pb(Mg2/3Nb1/3)O3–xPbTiO3 (PMN–xPT) ferroelectric ceramics were prepared and the relationship between flexoelectricity and PT content was systematically investigated. The largest flexoelectric response (∼550 μC/m) was observed in the Sm-doped PMN–32PT ceramic, which should be accounted for in the reorientation of the polar nanoregions. At room temperature, the flexoelectric response of Sm-doped PMN–32PT ceramic is an order of magnitude higher than that of the parent PMN–PT ceramics and even 50% higher than that of Bi–PMN–32PT ceramic (∼300 μC/m). Such a big increment is directly related to the greater local structural heterogeneity caused by Sm3+ ions into PMN–PT. Therefore, the result presented in this paper verifies that introducing local structural heterogeneity is a feasible approach to achieve ultrahigh flexoelectricity.

Ultratransparent PMN‐PT Electro‐Optic Ceramics and Its Application in Optical Communication

AbstractElectro‐optic (E‐O) materials are essential to modern information society, especially for optical switches, modulators, and filters in optical communication. In this paper, ultrahigh transparent (1−x)Pb(Mg1/3Nb2/3)O3‐xPbTiO3 (PMN‐PT) relaxor ferroelectric ceramics are fabricated. The effect of Sm‐doping content (0, 0.5, 1.0, 1.5, and 2.0 mol%) on PMN‐PT transparent ceramics is systematically investigated on the optical transparency, electro‐optic coefficient, extinction ratio, and half‐wave voltage. Results indicate that 0.5 mol% Sm‐doped PMN‐PT ceramic shows the optimal comprehensive performance, including high transparency of 69.6%, large quadratic E‐O coefficient of 35 × 10–16 m2 V−2, decent extinction ratio of 32 dB, and low half‐wave voltage (113 V at d = L = 1 mm). An electro‐optic modulator is designed based on the PMN‐PT transparent ceramics and its application in optical communication is realized, such as rapid information modulation, analog signal (audio frequency), and digital signal (graphic patterns) transmission. These results indicate that Sm‐doped PMN–xPT transparent ceramics are promising candidates for E‐O modulation applications.

Connecting the Multiscale Structure with Macroscopic Response of Relaxor Ferroelectrics

AbstractLead‐based relaxor ferroelectrics are characterized by outstanding piezoelectric and dielectric properties, making them useful in a wide range of applications. Despite the numerous models proposed to describe the relation between their nanoscale polar structure and the large properties, the multiple contributions to these properties are not yet revealed. Here, by combining atomistic and mesoscopic‐scale structural analyses with macroscopic piezoelectric and dielectric measurements across the (100–x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN–xPT) phase diagram, a direct link is established between the multiscale structure and the large nonlinear macroscopic response observed in the monoclinic PMN‐xPT compositions. The approach reveals a previously unrecognized softening effect, which is common to Pb‐based relaxor ferroelectrics and arises from the displacements of low‐angle nanodomain walls, facilitated by the nanoscale polar character and lattice strain disorder. This comprehensive comparative study points to the multiple, distinct mechanisms that are responsible for the large piezoelectric response in relaxor ferroelectrics.

A quasi‐linear piezoelectric strain behavior of [001] textured rhombohedral PMN–24%PT ceramic

AbstractHighly textured (1–x)Pb(Mg1/3Nb2/3)O3‐xPbTiO3 (PMN–xPT) piezoelectric ceramics were fabricated. It was found that [001] textured rhombohedral PMN–24%PT ceramic exhibited a quasi‐linear piezoelectric strain behavior with low hysteresis. The strain hysteresis of PMN–24%PT ceramic was reduced from 22.5% to 9% at 30 kV/cm using the texture method. Accurate displacement was generated by DC field using textured PMN–24%PT ceramic. The domain configurations in textured PMN–xPT ceramics were figured out using the chemical etching method. It was demonstrated that the quasi‐linear and low‐hysteretic strain behavior was due to a fixed domain configuration. We predict that the textured PMN–24%PT ceramic will facilitate the development of low‐voltage driving piezoelectric actuators with high precision.

Electrophysical Properties of PMN-PT-Ferrite Ceramic Composites.

Ferroelectromagnetic composites based on (1−x)PMN-(x)PT (PMN-PT) powder and Ni-Zn ferrite powder were obtained and are described in this work. As a ferroelectric component, we used (1−x)PMN-(x)PT solid solution (with x = 0.25, 0.28, 0.31, 0.34, 0.37, 0.40), synthesized using the sol-gel method. As a magnetic component, we used nickel-zinc ferrite, obtained using classic ceramic technology. The six compositions of PMN-PT used have rhombohedral symmetry, tetragonal one and mixture of these phases (morphotropic phase area), depending on x. The final ceramic composite samples were obtained using the classic methods involving the calcination route and pressureless final sintering (densification). The properties of the obtained ceramic composite samples were investigated, including microstructure SEM (scanning electron microscope), dielectric properties, electromechanical properties, and DC (Direct Current) electrical conductivity. Results showed that the microstructures of the PP-F composite samples characterized by larger grains were better crystallized, compared with the microstructures of the PMN-PT ceramic samples. The magnetic properties do not depend on the ferroelectric component of the composite samples, while the insertion of ferrite into the PMN-PT compound reduces the values of remnant and spontaneous polarization, as well as the coercive field. The dielectric measurements also indicated that the magnetic subsystem influences the dielectric properties. The present results show that the PP-F ceramic composite has good dielectric, magnetic, and piezoelectric properties, which predisposes this type of material to specific applications in microelectronics and micromechatronics.

Alternate current poling and direct current poling for Pb(Mg1/3Nb2/3)O3–PbTiO3 single crystals

We have investigated the effects of alternate current poling (ACP) for four different plates of [100]-oriented (100 – x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN–xPT, x = 28, 29, 30, 31) single crystals (SCs) obtained from one ingot. A record high piezoelectric coefficient d33 of 3000 pC N–1 for PMN–30PT SCs, and a high free dielectric permittivity of 8900 for PMN–28PT SCs by ACP, 27% higher than those of conventional direct current poling (DCP), were confirmed. X-ray analysis revealed a higher (004) peak intensity and angle of ACP SCs compared to those of DCP. We assume that ACP creates a monoclinic multiphase (MB and MC) and eliminates some portion of the tetragonal phase in SCs. In addition, (004) peak shifts were different between the different PT composition SC samples. This work demonstrates an ACP process with excellent cost performance can offer promising prospects and practical value for PMN–xPT SC piezoelectric transducers.

Multi‐scale domain structure observation and piezoelectric responses for [001]‐oriented PMN‐33PT single crystal

AbstractMultiple phase coexistence contributes to the extraordinary piezoelectric behavior of (1‐x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN–xPT) near the morphotropic phase boundaries (MPBs). By incorporating an optical path of crossed polarized light (PLM) into the commercialized Piezoelectric Force Microscope (PFM) (named as PLM‐PFM system), in situ domain structure observation from micro‐ to nanoscale, as well as measurement of the piezoelectric behavior for individual domains can be realized. For [001]‐oriented single crystal of 67Pb(Mg1/3Nb2/3)O3‐33PbTiO3 (PMN‐33PT), fine domain boundary structures of rhombohedral (R), tetragonal (T), and monoclinic (M) phases are revealed. Measurements of the electric field‐induced displacement as a function of the applied DC electric field (VDC) are performed for domains with different polarization vectors. Values for the electric field‐induced displacement are in descending order for c‐domains of the M, R, and T phases. For an individual phase of T or M, the displacement increases when the angle between the polarization vector and the applied electric field decreases. The multi‐scale perspective of the domain structures and the corresponding piezoelectric response helps in understanding the ultra‐high piezoelectric performance for PMN‐PT single crystals near MPB.

Pyroelectric sensor based on Pb(Mg1/3Nb2/3)1-xTixO3 single crystals for solid state hydrogen storage reactors

The pyroelectric effect is commonly used to construct infrared radiation detectors. To pay attention to the possibility of using this phenomenon in materials based on relaxor-ferroelectric such as Pb(Mg1/3Nb2/3)1-xTixO3 (lead titanium-lead magnesium niobate), single crystals from solid solution were grown using modified Bridgman method with x taken three different range (x = 0.25, 0.33 and 0.40).In this work the operation principles for pyroelectric sensor and their properties are presented, with a brief review on the temperature stability of the Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN–xPT) single crystals. It was shown that the pyroelectric and dielectric properties are strongly dependent on composition (PT content), as well as the temperature variation. The investigations have revealed that the best choice for pyroelectric performances is <111>oriented PMN–0.25 PT, although, the PMN–0.33 PT and PMN–0.40 PT owns much better temperature stability, and higher Curie temperature Tc.The PMN–xPT single crystals showed promising pyroelectric performances, they can be used as thermal sensors and may be associated with temperature management systems to improve the performance of solid state hydrogen reactors.

Multiscale field-induced structure of (1-x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 ceramics from combined techniques

The vast majority of studies on field-induced changes in (1–x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN–xPT) materials at the morphotropic phase boundary (MPB) have been performed on single crystals, while the more complex responses in polycrystalline materials have not yet been resolved. By using combined microscopy and diffraction techniques, this study aims to determine the structural changes induced by application of an electric field to two representative MPB compositions of the PMN–xPT family, namely, PMN–30PT with the initial Cm and Pm coexisting phases, and PMN–35PT with the P4mm and Pm phases. Both ceramic compositions are characterized by a hierarchical domain structure with domains present at different length-scales. Based on the applied field measurements, major contributing effects in both compositions are outlined and discussed with respect to the processes related to the monoclinic phase and the adaptive phase theory. It is shown that the highly mobile domain walls are largely involved, along with the field-induced polarization rotation in the monoclinic PMN–30PT, and a phase transition to a mainly tetragonal structure in PMN–35PT. These multiscale results elucidate important aspects of field-induced changes in PMN–xPT materials, contributing to the understanding of the complex electrical and electromechanical response of relaxor ferroelectrics.

Legendre polynomial modeling for vibrations of guided Lamb waves modes in [001]c, [011]c and [111]c polarized (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (x = 0.29 and 0.33) piezoelectric plates: Physical phenomenon of multiple intertwining of An and Sn modes

Guided wave devices have recently become one of the most important applications in the industry because such waves are directly related to applications in sensor technology, chemical sensing, agricultural science, fields of bio-sensing and surface acoustic wave (SAW) devices that are used in electronic filters and signal processing. On that account, this numerical investigation aims to study the propagation behavior of guided Lamb waves in a ( $1-x$ )Pb(Mg1/3Nb2/3)O3-x PbTiO3 [PMN-x PT] ( $ x=0.29$ or 0.33) piezoelectric single crystal plate. In fact, the PMN-xPT ( $ x=0.29$ or 0.33) piezoelectric crystals are being polarized along $[001]c$ , $ [011]c$ and $ [111]c$ of the cubic reference directions so that the macroscopic symmetries are tetragonal 4mm, orthogonal mm2 and rhombohedral 3m, respectively. Both open- and short-circuit conditions are considered. Here, the Legendre polynomial method is proposed to solve the guided Lamb waves equations. The validity of the proposed method is illustrated by comparison with the ordinary differential equation (ODE). The convergence of this method is discussed. Consequently, the converged results are obtained with very low truncation order M . This constitutes a major advantage of the present method when compared with the other matrix methods. There is cross-crossings among multiple modes for both symmetric ( $ S_{n}$ ) and the anti-symmetric ( $ A_{n}$ ) guided Lamb waves propagation. A displacement field has been illustrated to judge whether $S_{n}$ and $A_{n}$ modes cross with each other. Moreover, electric displacement, stress field and electric potential for the open-circuit case were presented for both $ S_{0}$ and $ A_{0}$ Lamb modes.

Strain-induced nanostructure of Pb(Mg1/3Nb2/3)O3–PbTiO3 on SrTiO3 epitaxial thin films with low PbTiO3 concentration

The singularity of the structure in (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN–xPT) (x = 0–50 mol %) epitaxial thin films of 100 nm thickness was investigated from the viewpoint of the localized residual strain in the nanoscale. The films were deposited on SrTiO3 (STO) (001) single-crystal substrates by chemical solution deposition (CSD) using metallo-organic decomposition (MOD) solutions. X-ray and electron diffraction patterns revealed that PMN–xPT thin films included a single phase of the perovskite-type structure with the cube-on-cube orientation relationship between PMN–xPT and STO: (001)Film ∥ (001)Sub, [100]Film ∥ [100]Sub. X-ray reciprocal space maps showed an in-plane tensile strain in all the compositional ranges considered. Unit cells in the films were strained from the rhombohedral (pseudocubic) (R) phase to a lower symmetry crystal system, the monoclinic (MB) phase. The morphotropic phase boundary (MPB) that split the R and tetragonal (T) phases was observed at x = 30–35 for bulk crystals of PMN–xPT, whereas the strain suppressed the transformation from the R phase to the T phase in the films up to x = 50. High-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM) analysis and its related local strain analysis revealed that all of the films have a bilayer morphology. The nanoscale strained layer formed only above the film/substrate semi-coherent interface. The misfit dislocations generated the localized and periodic strain fields deformed the unit cells between the dislocation cores from the R to an another type of the monoclinic (MA) phase. Thus, the singular and localized residual strains in the PMN–xPT/STO (001) epitaxial thin films affect the phase stability around the MPB composition and result in the MPB shift phenomena.

Dielectric and ferroelectric properties of (1-x)PMN-(x)PT synthesized by co-precipitation method

ABSTRACTThe paper presents synthesis of (1-x)PMN-(x)PT (PMN-PT) near morphotropic phase boundary (MPB) i.e. for x = 0.25, 0.31, 0.33 and 0.35, using hydroxide co-precipitation method. Further, PMN-PT compositions under investigation were systematically characterized for density, structural, morphological, dielectric and ferroelectric properties. X-ray diffraction data reveals single phase formation of PMN-PT. The scanning electron microscopy (SEM) images were recorded and used to understand morphology of the samples. In present study, it was noted that the PMN-PT composition with x = 0.25 exhibits the maximum value of dielectric constant (ϵ) and saturation polarization (Pmax) amongst the PMN-PT compositions under investigation.

Features of the Relaxor State in the Simple-Perovskite Mixed-Oxide System (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3

The mixed-oxide system (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN–xPT) has a simple perovskite structure and exhibits relaxor behavior for 0 ≤ x ≤ 0.30 (low Ti contents). To understand the relaxor state in PMN–xPT, the crystallographic features of the ferroelectric states were investigated via transmission electron microscopy, taking advantage of Friedel’s law failure. Polar regions having 〈110〉C and 〈001〉C components were observed separately both below and near Tm, the maximum temperature of the dielectric permittivity for the relaxor. As a result, the relaxor state for 0 < x ≤ 0.30 was identified as an assembly of nanometer-scale polar domains with rhombohedral symmetry. On the other hand, the ferroelectric states for 0.40 ≤ x ≤ 0.70 are characterized by a ferroelectric MC-type monoclinic state, having a polarization vector in the {100}C planes. Thus, the FR/FMC boundary around x = 0.35 was identified as the morphotropic phase boundary (MPB), nearly parallel to the temperature axis.

Kinetics of nucleation of thermodynamically ordered ferroelectric phases in PbMg1/3Nb2/3O3–xPbTiO3 crystals with different compositions

The kinetics of electric field-induced nucleation of ordered ferroelectric phases from a mixed glassy relaxor state has been studied in a number of single-crystal (1–x)PbMg1/3Nb2/3O3–xPbTiO3 (PMN–xPT) solid solutions (x = 29, 33, 35%) lying in a morphotropic phase region. It is shown that the formation of these phases and fast establishment of a macroscopic polarization are preceded by some delay time, depending on the electric field strength and temperature. It is found that the monoclinic phase is thermodynamically stable at room temperature in all the compounds in the time (~3000 s) and electric field (~1 kV/cm) ranges under study, whereas the monoclinic phase of the compound with x = 35% transforms, at temperatures near the temperature of the morphotropic phase transition after insignificant time interval of ~100 s, to another stable ferroelectric tetragonal phase.

Broadband light-scattering spectroscopy on fractal and non-fractal relaxors

We show the quasi-elastic light scattering (QELS) spectra of two groups of relaxors: the first group includes relaxors that exhibit glasslike low-temperature thermal conductivity and heat capacity, namely, Pb(Mg1/3Nb2/3)O3 (PMN), (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN–xPT), Pb(Zr1/3Nb2/3)O3 (PZN), and (Na1/2Bi1/2)TiO3 (NBT). The other group consists of relaxors exhibiting a normal (crystal) temperature dependence of the thermal conductivity and heat capacity, namely, K1−xLixTaO3 (KLT) and KTa1−xNbxO3 (KTN). The crystals of the first group yielded self-similar (power-law) QELS spectra, indicating the existence of fractal networks/clusters of polar nanoregions, while those of the second group did not show any self-similarity in the QELS spectra. These results imply that the glasslike low-temperature thermal conductivity and heat capacity in relaxors can be attributed to the vibrational modes specific to fractal networks/clusters formed by polar nanoregions.

Elaboration and characterization of PMN–xPT solid ceramics used in a numerical simulation of a piezoelectric transducer for a loudspeaker application

Solid ceramics (1 − x)PbMg1/3Nb2/3O3–xPbTiO3 (PMN–xPT) have been prepared and characterized in the present work. Three PMN–xPT compositions were used with x taking the values of 0.31, 0.33 and 0.35. For the three compositions, an analysis of the dielectric behavior has been made, in order to determine the phase transition temperatures and Curie’s temperatures by measuring the dielectric constants and the dielectric losses as a function of temperature and frequency. A typical behavior to that of ferroelectric relaxor materials was noted by the increase of the PT’s rate. Ferroelectric character was analyzed by studying the evolution of polarization as a function of the applied field for the different samples, with the variation of the temperature. The hysteresis loop was strongly modified by the action of the temperature. The remnant polarization, as well as the coercive field, decreases with the increase of the temperature and increase with the increase of the applied field. Due to their high dielectric and ferroelectric properties, a numerical simulation by a finite element analysis software was made on PMN–0.35PT pellets, used for a loudspeaker application. The mechanical and acoustic behaviors of the piezoelectric transducer were investigated.

Domain Structure Evolutions During the Poling Process for [011]‐Oriented PMN–xPT Crystals Across the MPB Region

The poling effect on the [011]‐oriented (1−x)Pb(Mg1/3Nb2/3)O3‐xPbTiO3 (PMN–xPT) single crystals across the morphotropic phase boundary (MPB) was studied. The dielectric and piezoelectric properties were investigated as a function of the poling field. Domain structure evolutions during the poling process were recorded. In the unpoled PMN–xPT phase diagram, an apparent rhombohedral (R)‐tetragonal (T) phase boundary exists. With room‐temperature poling, the structure transformation sequence strongly depends on the composition. The crystal experiences a direct transition to the 2R/2T domain state in the rhombohedral or tetragonal phase field beyond the MPB region, whereas within the MPB zone it is hard to achieve the 2R/2T engineered configuration although the initial state is either rhombohedral or tetragonal as well. The piezoelectric responses of the MPB·PMN–xPTs are extraordinary weak (d33 ~ 250 pC/N), in contrast to the [011]‐oriented multidomain PMN–xPTs with ultrahigh‐piezoelectric coefficient (d33 &gt; 1000 pC/N). We demonstrate that a slight composition variation near the MPB will significantly influence the domain evolution route and piezoelectricity for the [011]‐oriented PMN–xPT crystals. We also confirm the feasibility to realize the 2R/2T engineered domain configuration for the [011]‐oriented MPB crystals, which will extend the desired portion of the Bridgeman‐grown boules with optimal piezoelectric properties.