PMN PT Research Articles

The investigation of reversible strain and polarization effect in (011)-La0.9Ba0.1MnO3 film using field effect configuration

We have investigated the influence of the electric bias field on the magnetic and transport properties of (011)-oriented La0.9Ba0.1MnO3 (LBMO) thin film epitaxially grown on (011)-0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (PMN–PT) single crystal substrate. It was found that strain and polarization effects induced by electric bias coexist in the whole temperature range and both of them can modulate the transport properties of (011)-LBMO on PMN–PT. The relative change of resistance ΔR/R exhibits peak values of −22% and −32% for bias fields of +12 and −12 kV/cm, respectively, around metal-insulator transition temperature, TMI. However, the sign of ΔR/R shows polarity dependence at temperature far below TMI. Further careful analysis demonstrates that these two opposite behaviors can be ascribed to the different influence of strain and polarization effects on transport properties.

Large electrocaloric effect of highly (100)-oriented 0.68PbMg1/3Nb2/3O3–0.32PbTiO3 thin films with a Pb(Zr0.3Ti0.7)O3/PbOx buffer layer

0.68PbMg1/3Nb2/3O3–0.32PbTiO3 (PMN–PT) thin films with a lead zirconate titanate Pb(Zr0.3Ti0.7)O3 (PZT)/PbOx buffer layer were deposited on Pt/TiO2/SiO2/Si substrates by radio frequency magnetron sputtering technique, and pure perovskite crystalline phase with highly (100)-preferred orientation was formed in the ferroelectric films. We found that the highly (100)-oriented thin films possess not only excellent dielectric and ferroelectric properties but also a large electrocaloric effect (13.4K at 15V, i.e., 0.89K/V) which is attributed to the large electric field-induced polarization and entropy change during the ferroelectric–paraelectric phase transition. The experimental results indicate that the use of PZT/PbOx buffer layer can induce the crystal orientation and phase purity of the PMN–PT thin films, and consequently enhance their electrical properties.

Theoretical analysis of ultrahigh electromechanical coupling surface acoustic wave propagation in Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 crystals

The propagation characteristics of surface acoustic waves (SAWs) on the Y-cut X-propagating Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PMN–PT) substrate are theoretically analyzed. The results indicate the existence of a shear horizontal (SH)-type SAW with an ultrahigh electromechanical coupling factor K2. Different metal layers (Au, Al, and Cu) were examined as the electrode material. With gold, the maximum K2 for the SH SAW reaches 72.6%, while it is smaller (69.7%) for Al or Cu. There also exists a Rayleigh SAW causing the spurious response. It is shown that the response can be suppressed sufficiently by properly adjusting the thickness of the metal layer. This feature is very attractive for the realization of ultrawideband SAW filters. Variation of SAW properties with the substrate rotating angle θ was also investigated. The result indicates that θ = 0° is the best due to the relatively larger K2 for SH SAW and lower value for Rayleigh spurious response.

Microstructural and electrical properties of 0.65Pb(Mg 1/3Nb 2/3)O 3–0.35PbTiO 3 (PMN–PT) epitaxial films grown on Si substrates

Epitaxially grown PMN–PT thin films using the PMN–PT single crystal targets were prepared at 550 °C on appropriate buffer layers of LSCO/CeO 2/YSZ deposited on a Si substrate using pulsed laser deposition. The micro-structural and the electrical properties of the films were investigated as a function of the film thickness. The PMN–PT films with the thickness from 200 to 600 nm exhibited an epitaxial nature with a pure perovskite structure. On the other hand, the films above 700 nm included a pyrochlore phase embedded in the perovskite structure although they exhibited an epitaxial nature. A pyrochlore phase included in the films above 700 nm thickness decreased the dielectric constant and the ferroelectric properties of the PMN–PT films.

In situ dynamical control of the strain and magnetoresistance of La 0.7Ca 0.15Sr 0.15MnO 3 thin films using the magnetostriction of Terfenol-D alloy

We fabricated a magnetoelectric laminate structure consisting of a magnetostrictive Tb 0.3Dy 0.7Fe 1.92 (Terfenol-D) plate bonded to a La 0.7Ca 0.15Sr 0.15MnO 3 (LCSMO)/0.67Pb(Mg 1/3Nb 2/3)O 3-0.33PbTiO 3 (PMN–PT) structure where a LCSMO film was epitaxially grown on a PMN–PT single crystal substrate. When a dc magnetic field is applied perpendicular to the film plane, the magnetoresistance of the LCSMO film in the paramagnetic (ferromagnetic) state for the LCSMO/PMN–PT/Terfenol-D structure is larger (smaller) than that for the LCSMO/PMN–PT structure without Terfenol-D. These effects are caused by the magnetostriction-induced in-plane compressive strain in the Terfenol-D, which are transferred to the PMN–PT substrate, leading to a reduction in the in-plane tensile strain of the epitaxial LCSMO film and thereby modifying the magnetoresistance of the film.

Templated Grain Growth of 〈001〉-Textured 0.675Pb(Mg1/3Nb2/3)O3-0.325PbTiO3 Piezoelectric Ceramics for Magnetic Field Sensors

〈001〉-textured 0.675Pb(Mg1/3Nb2/3)O3–0.325PbTiO3 (PMN–32.5PT) ceramics were synthesized through templated grain growth method using BaTiO3 (BT) platelets as templates. A systematic investigation was conducted on delineating the texture development and microstructure evolution as a function of heat-treatment conditions. It was found that BT has very good stability in PbO-rich PMN–PT environment. A high texture degree of 90% was achieved using 5 vol% BT. Dielectric, ferroelectric, and piezoelectric properties were measured to understand the influence of sintering time, texture degree, and BT heterogeneity on the electrical characteristics. It was found that with increasing sintering time and texture degree, the piezoelectric constant d33 increases while the dielectric constant decreases, resulting in about 50% improvement of g33 as compared with random ceramics. Unipolar strain-field measurements of textured ceramics exhibited 0.27% strain at 30 kV/cm. The changes in large-signal response of textured ceramics were more obvious than small-signal measurement, indicating that 〈001〉 crystallographic texture enhances the piezoelectric response due to favorable domain configuration. Using the textured sample, a magnetoelectric laminate was fabricated and characterized for low magnetic-field sensitivity.

Synthesis and thermochemistry of relaxor ferroelectrics in the lead magnesium niobate–lead titanate (PMN–PT) solid solutions series

The energetics of the (1 − x)PMN–xPT solid solutions have been investigated using high temperature oxide melt solution calorimetry in 3Na2O·4MoO3solvent at 702 °C. The solid solutions show positive heats of mixing, reflecting the changes in structure from cubic to tetragonal to monoclinic and the morphotropic phase transition. The synthesis of a perovskite phase without a secondary pyrochlore phase depends on the annealing temperature and time. The enthalpies of reactions involved in synthesis and decomposition of the PMN perovskite were measured for the first time by oxide melt solution calorimetry. The decomposition of perovskite to pyrochlore plus MgO and PbO is energetically favorable, as is the formation of perovskite from columbite and lead oxide.

Influence of residual stress on magnetoelectric coupling of bilayered CoFe2O4/PMN–PT thin films

Multiferroic CoFe2O4/0.68Pb(Mg1/3Nb2/3)O3–0.32PbTiO3 (CFO/PMN–PT) bilayered thin films with different CFO layer thicknesses were prepared on Pt/Ti/SiO2/Si substrates using the sol–gel technique. The bottom PMN–PT layer exhibited a highly (111) preferred orientation as conformed by a bidimensional (2D) planar X-ray diffractometer (XRD2). The influence of the thickness on the ferroelectric, dielectric, ferromagnetic, and magnetoelectric (ME) properties of the CFO/PMN–PT bilayered thin films was investigated. The residual stress of the top CFO layer films was characterized by means of grazing incidence X-ray diffraction. The ME signal is strongly dependent on the residual stress status of the CFO layer, which provides direct evidence for a stress-induced ME coupling mechanism in the multiferroic bilayered thin films. The maximal ME coupling coefficient of the bilayered thin films reaches up to about 65.2 mV cm−1Oe−1, which was higher than that reported previously.

Control of the strain and magnetoresistance of LaMnO3+δ thin films using the magnetostriction of Terfenol-D alloy

We have fabricated a magnetoelectric laminate structure composed of magnetostrictive Tb0.3Dy0.7Fe1.92 (Terfenol-D) alloy and LaMnO3+δ (LMO)/0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 (PMN–PT) structure where the LMO film is epitaxially grown on the piezoelectric PMN–PT single-crystal substrate. When an external dc magnetic field is applied perpendicular to the film plane, the magnetoresistance of the LMO film at 220 K under a magnetic field of 1.2 T for the LMO/PMN–PT/Terfenol-D structure is enhanced by 31.6% with respect to that for the LMO/PMN–PT structure without Terfenol-D. Measurements of the magnetoelectric effects of the LMO/PMN–PT/Terfenol-D structure indicate that the strain induced by the magnetostriction of the Terfenol-D alloy is transferred to the PMN–PT substrate, which induces changes in the strain state of the PMN–PT substrate, thereby modifying the strain and magnetoresistance of the epitaxial LMO film.

Epitaxial 0.65PbMg 1/3Nb 2/3O 3–0.35PbTiO 3 (PMN–PT) thin films grown on LaNiO 3/CeO 2/YSZ buffered Si substrates

Ferroelectric PMN–PT thin films with a thickness of 600 nm were epitaxially grown on buffered Si (0 0 1) substrates at a substrate temperature that ranged from 550 to 700 °C using pulsed laser deposition (PLD). LaNiO 3 (LNO) electrode thin films with a resistivity of ∼1900 μΩ cm were epitaxially grown on CeO 2/YSZ buffered Si (0 0 1) substrates. The PMN–PT thin films grown at 600 °C on LNO/CeO 2/YSZ/Si substrates had a pure perovskite and epitaxial structure. The PMN–PT films exhibited a high dielectric constant of about 1818 and a low dissipation factor of 0.04 at a frequency of 10 kHz. Polarization-electric-field (P-E) hysteresis characteristics, with a remnant polarization of 11.1 μC/cm 2 and a coercive field of 43 kV/cm, were obtained in the epitaxial PMN–PT films.

Effects of annealing technique and TiO 2 seed layer on the phase composition of 0.7Pb(Mg 1/3Nb 2/3)O 3–0.3PbTiO 3 film

The lead magnesium niobate–lead titanate (PMN–PT) thin films with and without the TiO 2 seed layer were prepared by a pulsed laser deposition (PLD) deposited on Pt/Ti/SiO 2/Si substrates. The films were treated by two-step annealing and normal annealing with rapid thermal annealing (RTA). The effects of two-step annealing and the TiO 2 seed layer on the phase composition of PMN–PT films were studied. The results show that the PMN–PT film with TiO 2 seed layer can gain a pure perovskite phase with a high (1 0 0) preferential orientation after the two-step annealing technique.

Recent developments on high Curie temperature PIN–PMN–PT ferroelectric crystals

Pb(In0.5Nb0.5)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PMN–PT) ferroelectric crystals attracted extensive attentions in last couple years, due to their higher usage temperatures range (>30°C) and coercive fields (∼5kV/cm), meanwhile maintaining similar electromechanical couplings (k33>90%) and piezoelectric coefficients (d33∼1500pC/N), when compared to their binary counterpart Pb(Mg1/3Nb2/3)O3–PbTiO3. In this article, we reviewed recent developments on the PIN–PMN–PT single crystals, including the Bridgman crystal growth, dielectric, electromechanical, piezoelectric and ferroelectric behaviors as functions of temperature and dc bias. Mechanical quality factor Q was studied as a function of orientation and phase. Of particular interest is the dynamic strain, which related to the Q and d33, was found to be improved when compared to the binary system, exhibiting the potential usage of PIN–PMN–PT in high power application. Furthermore, PIN–PMN–PT crystals exhibit improved thickness dependent properties, due to their small domain size, being on the order of 1μm. Finally, the manganese acceptor dopant in the ternary crystals was investigated and discussed briefly in this paper.

The compositional segregation, phase structure and properties of Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 single crystal

A ternary relaxor ferroelectric single crystal Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 was grown by the modified Bridgman method. The real compositions, phase structures and performances of different regions in the boule were characterized. The real composition deviated from the nominal composition, but the In/Pb ratio in the crystal remained nearly a constant. The piezoelectric coefficient d33, electromechanical coupling factor k33 and coercive field Ec after 〈011〉 poling can reach up to 1500pC/N, 0.90 and 4kV/cm, respectively. More importantly, the rhombohedral to tetragonal phase transition temperature (Trt) in PIN–PMN–PT single crystal with rhombohedral composition increased to 114°C, which made the ternary system single crystal fit for the applications in wider temperature range.

MPB design and crystal growth of PMN–PT–PZ relaxor ferroelectrics

Rhombohedral–tetragonal ferroelectric structural phase transition temperature (TR−T), far below the Curie temperature (Tc) in lead magnesium niobate–lead titanate (PMN–PT) relaxor ferroelectric single crystal, heavily restricts its further applications either as a sensor or transducer. To overcome this shortcoming, lead zirconate (PZ) was introduced into the PMN–PT pseudo-binary system to increase TR−T via the morphotropic phase boundary (MPB) composition design and optimization. According to the PMN–PT–PZ pseudo-ternary phase diagram, various compositions have been selected to discuss the relations between their phase structural transition and piezoelectric properties in the PMN–PT–PZ pseudo-ternary system. X-ray diffraction (XRD) investigation indicates clearly that PMN–PT–PZ ceramics with MPB compositions experience a typical structural phase transition process from rhombohedral phase to tetragonal phase. Remnant polarization (Pr=33.4μC/cm2) and piezoelectric coefficient (d33=1050pC/N) were obtained at the (001) cut PMN–PT–PZ single crystal. TR−T was increased up to 120°C by measuring its dependence of dielectric constant on temperature.

101]-Oriented Pb(Mg1/3Nb2/3)O3-PbTiO3 Single Crystals Under Electric Loadings: Polarization Rotation Linking MB, O, and R Phases

We report on the existence of monoclinic (MB), orthohombic (O), and rhombohedral (R) phases in [101]-oriented 74Pb(Mg1/3Nb2/3)O3–26PbTiO3 (PMN–26PT) single crystals under electric loadings. Before electric loadings, the [101]-oriented PMN–26PT single crystal is composed of R and monoclinic phases. Both MB and R phases are revealed after being poled in the [101] direction. When the single crystal is subjected to bipolar cyclic electric field, an MB phase bridges the reversal of domains of R phase. Reversal of the domains of MB phase is achieved by either 180° domain switching or non-180° domain switchings. Under static electric field, polarization rotation from R to MB again occurs, and as the field increases, phase transition from MB to O phase occurs. The O phase is metastable because it tends to change back to MB phase after the removal of electric field. The findings are of importance for understanding the microstructure characteristics of [101]-oriented PMN–PT single crystals that show the ultrahigh piezoelectric performances at the morphotropic phase boundary.

Electromechanical stability of electro-active silicone filled with high permittivity particlesundergoing large deformation

In this paper, an expression for the permittivity of electro-active silicone undergoing largedeformation with high permittivity particles filled uniformly has been proposed.Two expressions are proposed for the permittivity, one based on experimentaltests and the other based on the theory of composite material. By applying thethermodynamic model incorporating linear dielectric permittivity and nonlinearhyperelastic performance, the mechanical performance and electromechanicalstability of the coupling system constituted by silicone filled with PMN–PT havebeen studied. The results show that the critical electric field decreases, namelythe stability performance of the system declines when the content of PMN–PTc(v) increases and the electrostrictive coefficients increase. The results are beneficial for us tounderstand deeply the influence of the filled particle on the stability performance of siliconeand to guide the design and manufacture of actuators and sensors based on dielectricelastomers.

MEMS-based power generation system using contractile force generated by self-organized cardiomyocytes

This paper describes a novel hybrid mirco electro mechanical system (MEMS)-based power generation system that uses the contractile forces generated by self-organized cardiomyocytes. By directly seeding and culturing cardiomyocytes on a diaphragm made from single crystal lead magnesium niobate–lead titanate (PMN–PT), cell-driven electrical power generation can be easily realized: The mechanical stress induced by the contraction forces generated by self-beating cardiac cells is converted into electrical power by the piezoelectric effect. The PMN–PT materials are selected because not only of their highly favorable piezoelectric properties but also of their relatively low Young's modulus and biocompatibility. The low Young's modulus makes it possible for these materials to respond sensitively to external forces with a low frequency, and they are nontoxic for the culture of cardiac cells. The PMN–PT single crystal diaphragm used in this study is based on a one-sided, interdigitated, electrode design, which enables the use of a high piezoelectric d 33 coefficient and thereby allows effective energy conversion. Moreover, by adopting this design, electrodes can be isolated from the cell culture medium naturally and cardiac cell contraction can be observed under an inverted microscope through the gap between the electrodes. After four days of in vitro, the output voltage is measured to range from 1.48 to 4.19 mV. This proposed power generation mechanism is also proven to be feasible by the simulations of a multiphysics finite element model (FEM). In conclusion, we demonstrate our system to be a potentially useful micropower source either for micro/nano-robots or for micro-implantable devices. The same system can also be a useful test bed for the quantitative understanding of temporal cardiac cell dynamics.

Performance comparison of PZT and PMN–PT piezoceramics for vibration energy harvesting using standard or nonlinear approach

This paper reports the performance comparison of two common piezoelectric compositions for energy harvesting purposes, using either a standard or a nonlinear technique. Unlike single crystals, piezoelectric ceramics are quite easy to obtain, and thus their application to realistic applications is feasible. This study focuses on two compositions: PZT + 1 mol% Mn and PMN–25PT, obtained from sintering piezoelectric powders, and highlights the advantages and drawbacks for each of them. Then the obtained samples are evaluated for energy harvesting purposes, either by connecting them directly to the harvesting stage or by adding a nonlinear interface that consists of inverting the piezovoltage synchronously with the structure motion, leading to an artificial increase of the conversion abilities. The piezoceramics show a significant difference in power generation ability when using the classical energy harvesting technique. However, it is demonstrated that the use of the nonlinear treatment on the output voltage of the transducers leads to a great reduction in this discrepancy in spite of the difference in ceramic compositions.

Label free detection of white spot syndrome virus using lead magnesium niobate–lead titanate piezoelectric microcantilever sensors

We have investigated rapid, label free detection of white spot syndrome virus (WSSV) using the first longitudinal extension resonance peak of five lead–magnesium niobate–lead titanate (PMN–PT) piezoelectric microcantilever sensors (PEMS) 1050–700 μm long and 850–485 μm wide constructed from 8 μm thick PMN–PT freestanding films. The PMN–PT PEMS were encapsulated with a 3-mercaptopropyltrimethoxysilane (MPS) insulation layer and further coated with anti-VP28 and anti-VP664 antibodies to target the WSSV virions and nucleocapsids, respectively. By inserting the antibody coated PEMS in a flowing virion or nucleocapsid suspension, label free detection of the virions and nucleocapsids were respectively achieved by monitoring the PEMS resonance frequency shift. We showed that positive label free detection of both the virion and the nucleocapsid could be achieved at a concentration of 100 virions (nucleocapsids)/ml or 10 virions (nucleocapsids)/100 μl, comparable to the detection sensitivity of polymerase chain reaction (PCR). However, in contrast to PCR, PEMS detection was label free, in situ and rapid (less than 30 min), potentially requiring minimal or no sample preparation.

Effects of ferroelectric-poling-induced strain on the transport and magnetic properties of La7/8Ba1/8MnO3 thin films

We have investigated the effects of the strain induced by ferroelectric poling on the transport and magnetic properties of La7/8Ba1/8MnO3 (LBMO) thin films epitaxially grown on ferroelectric 0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 (PMN–PT) single-crystal substrates. The ferroelectric poling reduces the in-plane tensile strain of the film, giving rise to a decrease in the resistivity and an increase in the magnetization, Curie temperature, and magnetoresistance of the LBMO film. These strain effects are explained within the framework of coexisting phases whose volume fractions are modified as a result of the reduction in the tetragonal distortion of MnO6 octahedra induced by ferroelectric poling. An investigation of the effects of polarization reversal on the transport properties of the LBMO film indicates that the ferroelectric-poling-induced strain effects dominate over the ferroelectric field effects in the LBMO/PMN–PT structure.