Magnesium Niobate-lead Titanate Research Articles

Infrared-driven pyroelectric effect in magnetoelectric sensor for suspended on-chip magnetic nanoparticles quantification

Precise and real-time quantification of suspended magnetic nanoparticles (MNPs) is essential for augmenting the efficacy of the present MNP-based lab-on-a-chip systems. Existing MNP quantification techniques use bulky external electromagnets, which make such techniques expensive, energy-inefficient, and result in significant side effects on the surrounding healthy tissues. Here, we report on the development of an infrared-driven, Ni/lead magnesium niobate–lead titanate (PMN–PT) magnetoelectric (ME) heterostructure-based sensor that enables rapid assessment of the suspended MNPs in a fluidic environment without using an external magnetic field. The injected MNPs are captured by the generated magnetic field gradient of the Ni thin film. Subsequently, the optothermal-pyroelectric property of the underlying PMN–PT layer is utilized to quantitatively assess the MNPs' concentration. Under the incident infrared pulse at zero bias voltage, the device shows different transient photocurrent responses against varied MNP concentrations with a sensitivity of 0.29 nA mg−1 ml and a response time of less than 2 s. Such a ME device can improve the efficacy of current ME-based lab-on-a-chip systems, where a single device can capture, manipulate, as well as quantitatively assess the MNPs efficiently for critical biomedical applications such as drug delivery, drug regulation, and hyperthermia.

Electrical and optical properties of Nd3+-doped rhombohedral Pb(Mg1/3Nb2/3)O3–PbTiO3 ferroelectric single crystal

Lead Magnesium Niobate Titanate 0.74 Pb(Mg1/3Nb2/3)O3-0.26PbTiO3 (0.74PMN-0.26 PT) single crystal doped with 1 mol% Nd3+ was grown by a modified Bridgman approach. Powder X-ray diffraction exhibited perovskite structure containing rhombohedral phase. The dielectric constants of various orientations with temperature were determined. We observed that the polarization process increases the crystal optical performances. The transmittance is significantly increased after poled along [011] direction. Optical properties changes were interpreted by electric domain structure. Energy band gaps were obtained by Tauc equation. Nd3+ has a strong emission transition band near 1062 nm; the long radiation lifetime of 148 μs indicates a low quenching effect. For the Nd-doped PMN-PT single crystals, their optical and electrical performances have been explored to extend the applications in medical, military and practical industrial production.

Effects of Poling on Electrical Properties of Flexible Piezoelectric Composites with Natural Rubber Matrix

This work was done to study effects of electrical applied voltage on electrical properties of flexible piezoelectric composites with natural rubber (NR) matrices. Different amounts of lead magnesium niobate titanate (PMNT) as a piezoelectric phase were added into NR matrices. NR/xPMNT (where x = 0, 60, 80, 100, 120 and 150 phr) composites were consequently obtained. The composites were poled under 25 kV/cm electric field for 30 mins. For all the samples, tetragonality is enhanced after poling. Dielectric and ferroelectric properties, and generated electrical voltage of unpoled and poled samples were measured. For the samples with x ≤ 80 phr, the properties are not improved with the poling process. However, for x > 80 phr samples, the properties are significantly enhanced after poling. A percent increase in generated electrical voltage after poling tends to increase with increasing PMNT concentration. The overall result suggests that the NR/100PMNT composite is suitable for applications as high mechanical damage resistance piezoelectric sensors and generators.

Selective control of magnetism in FeAl/PIN-PMN-PT using an electric field

Mediating nonvolatile magnetism by purely electrical methods is a crucial challenge for the development of high-density and low energy consumption information storage. Research into most material systems, including ferromagnetic /ferroelectric heterostructures and, especially, magnetostriction/lead magnesium niobate-lead titanate (PMN-PT), has focused mainly on the nonvolatile strain-mediated converse magnetoelectric (ME) effect. The recent discovery of a type of FeAl/lead indium niobate (PIN)-PMN-PT heterostructure has provided an approach for electrical control of magnetism at room temperature. We demonstrate selective control of nonvolatile magnetism in (001)- and (111)-oriented FeAl/PIN-PMN-PT. In order to illustrate the behavior of electric field control of magnetism in (111)-oriented PIN-PMN-PT, a converse ME coupling mechanism is presented via polarization switching models. This mechanism indicates that the magnetization process is related to both the direction of polarization switching and the strain-mediated effect. By controlling the piezoresponse force microscopy (PFM) scan direction and analyzing the color contrast of the PFM images, we confirm the validity of the proposed models of polarization switching and demonstrate the validity of the mechanism. The results of this study may offer a method for the selective control of magnetism in nonvolatile multilevel data storage.

Dielectric behavior of functional paint/PMN-PT nanocomposite films

The detailed functionality of 0-3 paint/lead magnesium niobate-lead titanate (PMN-PT) composite films is investigated in terms of their dielectric and electric transport characteristics. The Paint/PMN-PT composite films have been fabricated by a conventional cost effective paint brushing technique. The properties investigated include, dielectric constants, ε' and ε'' as a function of temperature, frequency and composition. From the foregoing parameters, it is indicated that the dielectric constants increase with an increase of filler content, and temperature, providing information on the functionality of the films. The results reveal that the AC conducitivity, σAC, obeys the relation σAC = Aωs, and exponent s, was found to decrease by increasing the temperature.

CNTs-added PMNT/PDMS flexible piezoelectric nanocomposite for energy harvesting application

ABSTRACTThe flexible piezoelectric nanocomposites based on lead magnesium niobate titanate [Pb(Mg1/3Nb2/3)0.65Ti0.35O3; PMNT] particles in polydimethylsiloxane (PDMS) matrix were fabricated and characterized. PMNT powders are synthesized using the columbite precursor method. PMNT/PDMS flexible nanocomposites are then prepared by spin casting technique, where a small amount of carbon nanotubes (CNTs) is added into the PMNT/PDMS composite to enhance cross-links between PMNT particles and PDMS matrix. The phase and microstructure of the nanocomposite are investigated by using X-ray diffraction and scanning electron microscope (SEM). The electromechanical behavior is evaluated by using an autonomous pneumatic actuator. The flexible composite, occupying approximately 300 mm2, is capable of generating an open-circuit voltage (Voc) of 2.83 ± 0.24 V and a short-circuit current (Isc) signal of 0.33 ± 0.01 µA across 10 Ω resistor under mechanical load of 300 N. The generated electrical charges are 29026 pC. The relative dielectric constant is measured at 10 kHz and found to be 6.76 ± 1.15. The piezoelectric PMNT/PDMS composite can potentially be used in a variety of applications such as wearable sensors, actuators, and energy harvesting for converting kinetic energy into useful electrical energy.

Polarization-independent electro-optic modulator based on PMNT electrically-controlled birefringence effect and Sagnac interferometer

Abstract A novel polarization-independent electro-optic modulator is proposed and investigated by using the electrically-controlled birefringence effect of transparent lead magnesium niobate titanate (PMNT) electro-optic ceramic and a Sagnac interferometer structure. The PMNT electro-optic ceramic is used as a phase retarder for two counter-propagating waves in which their polarization directions are adjusted to parallel and vertical to the electrical-field vector respectively. Then the output light intensity from the Sagnac interferometer will be modulated completely with the driven electrical signal and it is independent with the polarization direction of incident light. The extinction ratio is more than 21 dB. This modulated device will be very appropriate as a Q-switch or optical attenuator in the high power laser system.

Effect of processing options on ultra-low-loss lead–magnesium–niobium titanate thin films for high density capacitors

This work studies the impact of annealing temperatures on PMNT (lead–magnesium niobate–lead titanate, Pb(Mg0.33Nb0.67)0.65Ti0.35O3) thin films grown on a silicon substrate. The electrical properties of the thin films, such as dielectric constant and loss tangent, are shown to depend strongly on the annealing temperature, with the best electrical properties being achieved at the highest annealing temperature. It is seen that the perovskite phase is highest in the sample annealed at 750°C indicating that a relatively high temperature is necessary for complete transition of PMNT to the perovskite phase. The sample annealed at 400°C exhibits the lowest loss tangent of approximately 0.007 at a frequency of 1MHz.

Investigations on Morphology and Domain Configurations in 0–3 Lead Magnesium Niobate Titanate–Portland Cement Composites by SEM and PFM

Lead magnesium niobate titanate (PMNT) and Portland cement (PC) composite were fabricated as a new cement-based piezoelectric composite. Scanning Electron Microscope and Piezoresponse Force Microscope were used to investigate the morphology and domain configurations at the interfacial zone of PMNT-PC composites. Angular PMNT ceramic grains were found to bind well with the cement matrix and PMNT grains can be seen to disperse randomly in the cement matrix. Moreover, the angular shape PMNT particle contributes to better mechanical interlocking with the cement paste due to the angular aggregate having rough surface appearing to provide better mechanical interlocking with the cement paste.

Temperature behavior of electrical properties of high-k lead–magnesium–niobium titanate thin-films

This paper reports on the temperature dependence of the electrical properties of high-k lead–magnesium–niobium titanate thin films processed with different compositions (with and without nanoparticles) and with different annealing temperatures (450°C and 750°C). These characterization results support the ongoing investigation of the material's electrical properties which are necessary before the dielectric can be used in silicon-based IC applications.

Effects of Carbon Nanofiber on Dielectric Properties of PMN/CNFs/EP Composites

A kind of new composite material composed of piezoelectric ceramic lead magnesium niobate-lead zirconate-lead titanate (PMN)/carbon nanofibers (CNFs)/epoxy resin (EP) were prepared by a resin casting method. The effects of carbon nanofibers on dielectric properties of PMN/CNFs/EP composites were investigated in this paper. The concetration of CNFs had significant effects on dielectric constant, dielectric loss, dielectric frequency dependence and dielectric temperature dependence of PMN/CNFs/EP composites. When the content of CNFs increased from 0 to 0.8 wt% of the epoxy resin, the dielectric constant at 1 kHz increased sharply from 13.6 to 158, and the dielectric loss increased from 0.0524 to 2.59. In plots of the dielectric constant against frequency and dielectric loss against frequency, the dielectric constant and dielectric loss reduced dramatically at lower frequency ranging from zero to about 105 Hz, then approach to be stable at frequency higher than 105 Hz. Moreover, as to the effects of temperature on dielectric constant and dielectric loss of PMN/CNFs/EP composites, the dielectric constant of composite increased ranging from 25°C to 160°C, and the dielectric loss of composite also showed increase besides that with CNFs content 0.8 wt%.

Evaluation of process parameters and nanoparticle seeding ofsol–gel derived lead–magnesium–niobium titanate thin films

A near morphotropic phase boundary lead–magnesium–niobium titanatematerial system was synthesised by the sol–gel method; its thin filmswere deposited with or without nanoparticle (np) seeding and processedby the rapid thermal annealing. Influences of some process parameters andthe np seeding on various properties of the resultant films were systematicallyinvestigated. Although no reduction in annealing temperature was achievedupon np seeding, the results indicated that nps might indeed play a role asnucleation centres during the crystallisation. All in all, the lead–magnesium–niobiumtitanate thin film system described here (particularly those annealedat higher temperatures) appeared to be suitable for its potential applicationsin wireless communication systems as ultrahigh dielectric constant ϵvalue capacitors; the unexposed film annealed at 750°C, for instance,exhibited the highest dielectric constant ϵ (1425)with a low loss (loss tangent, ∼0·04) along with a stronglypronounced perovskite phase (96·5%).

Optical characteristics of transparent PMNT ceramic and its application at high speed electro-optic switch

The optical characteristics of transparent lead magnesium niobate titanate (PMNT) electro-optic ceramic, including the electro-optic phase modulation, electric hysteresis property and thermo-optic coefficient, are investigated in detail. Based on this novel ceramic, a polarization independent electro-optic switch by using fiber Sagnac interferometer (FSI) structure is realized. An initial π-shift is introduced into the Sagnac loop to eliminate the effect of the polarization orientation of the incident light on the switch performance. Then an electrically controllable PMNT phase retarder is used to switch the optical signal between the reflection and transmission ports. Some theoretical analyses are given and the switch performances are also discussed, including the thermal characteristic and different switching frequency response.

Giant magnetoelectric effects in multilayered composites of cobalt ferrite and lead magnesium niobate titanate

The magnetoelectric (ME) coupling responses of [CoFe2O4/(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3]n, represented as (CFO/PMNT)n, multilayered composites were theoretically investigated by using an average method. It is found that a stronger interface coupling could be obtained in multilayers than in bilayers if the number of layers (n) is reasonably increased. Using an empirical dependence of the interface coupling parameter on the number of layers n, it is theoretically estimated that the ME coupling effect is first enhanced and then deteriorated with the gradual increase in n. The best ME response is estimated to occur at n=15, where the transverse ME voltage coefficient αE,31 reaches as high as 658 mV·cm−1·Oe−1. Moreover, it is theoretically found that the ME coupling effect in (CFO/PMNT)n multilayered composites is strongly dependent on the volume fraction of the piezoelectric (or magnetostrictive) phase, and the ME voltage coefficient for transverse field orientation (αE,31) is estimated to be roughly 90% higher than that for the longitudinal case (αE,33), revealing a large anisotropy in the ME coupling effect of (CFO/PMNT)n multilayered composites. These findings pave the way for experimental achievement of strong ME coupling responses, and provide important implications for the design and performance optimization of related devices comprising this kind of multiferroic magnetoelectric materials.

Effect of Compressive Stress on the Ferroelectric Hysteresis Behavior in 0-3 PMN-PT/Cement Composites

Lead magnesium niobate titanate (PMN-PT)—Portland cement (PC) composites were produced. PMN- PT amount used in this work were 30, 50, and 70% by volume. The effects of PMN-PT content (using 30%, 50%, 70% PMN-PT) and stress on the ferroelectric polarization-electric field (P-E) hysteresis of the composites are reported in this present work. From the results, it was found that there was an increase in the instantaneous remnant polarization (Pir ) when PMN- PT amount increased while Pir was found to decrease when the stress was increased from 0 to 57 MPa.

Fiber Sagnac π-shifted interferometer for a polarization-independent PMNT high-speed electro-optic switch

We propose and analyze experimentally a high-speed polarization-independent lead magnesium niobate titanate (PMNT) electro-optic switch using a π-shifted fiber Sagnac interferometer (FSI). In the proposed switch, the PMNT high-speed electro-optic ceramic is used as a phase retarder for two counterpropagating waves, which can switch the energy between the reflection and transmission ports of the FSI. Because of an initial π shift introduced into the FSI by actively adjusting the polarization controller, the power response of the switch is independent of the polarization orientation of the incident light, which induces the polarization-independent characteristic of the switch. An optical switch with cross talk lower than -25 dB and a switching time of less than 200 ns is experimentally investigated. The insertion loss and electric hysteresis property are also demonstrated. Finally, a scheme to form the n × n switch matrix is proposed.

Ferroelectric Hysteresis Behavior of 0–3 PMNT-Cement Composites

Lead magnesium niobate titanate (PMNT)—Portland cement (PC) composites were produced. PMNT amount used in this work was 50% by volume. The ferroelectric (P-E) hysteresis behaviors were investigated as function of both frequency and electric field for all composites. From the results, it was found that there was an increase in both the instantaneous remnant polarization (Pir ) and coercive field (Eic ) when the applied field increased from 5 kV/cm to 20 kV/cm, Pir was found to increase from 1.5 to 9.8 μC/cm2 and Eic waas found to increase from 3.4 to 13.8 kV/cm. On the other hand, Pir and Eic were found to reduce from 11.1 to 8.8 μC/cm2 and from 10.8 to 15.3 kV/cm respectively, when the frequency was increased from 30–90 Hz; ascribed to the delayed response of the polarization reversal to the varying external field.

Effect of Particle Size on Dielectric and Ferroelectric Properties of 0–3 Lead Magnesium Niobate Titanate-Portland Cement Composites

The effect of lead magnesium niobate titanate (PMNT) particle size on the dielectric and ferroelectric properties of PMNT- Portland cement (PC) composites was investigated. PMNT of various particle sizes (75–425μm) were used at 50% by volume to produce the composites using the mixing and pressing method. Dielectric properties at various frequencies (0.1–20 kHz) and ferroelectrics behavior of the PMNT-Portland cement composites were investigated at room temperature. The results show that the dielectric constant of PMNT- Portland cement composite are found to increase ( = 154 for particle size 75 μm and = 275 for particle size 425 μm (at 1 kHz)), while dielectric loss decreased with increasing particle size of ferroelectric PMNT ceramics. Furthermore, the “instantaneous” remnant polarization (Pir ) of composites was found to increase with increasing PMNT particle size.

UV-/thermal processing of sol–gel-derived lead–magnesium–niobium titanate thin films

This work aimed to describe the sol–gel synthesis and preparation of a near-morphotropic phase boundary lead–magnesium–niobium titanate (PMNT) material system, and to investigate the influences of room-temperature-UV-irradiation and rapid thermal annealing (RTA) processes on the properties of its thin films. It was postulated that the use of UV-irradiation prior to thermal processing could play a role in the generation of a structural difference that would manifest itself via the formation of a higher film thickness, which was more pronounced at higher RTA temperatures The PMNT thin film system described here (particularly those annealed at higher temperatures) appeared to be potentially suitable for ultrahigh-value-capacitor applications; the unexposed film annealed at 750 °C exhibited the highest high k value (1425) with a strongly pronounced perovskite phase (97%).

Dielectric Properties of 0-3 Lead Magnesium Niobate Titanate (PMNT)-Ordinary Portland Cement (PC) Composites

The dielectric properties of lead magnesium niobate titanate, PMNT and portland cement, PC with x(0.67PMN-0.33PT)-(1-x)(PC) (where x = 0.3, 0.5, 0.7 and 1.0) composites were investigated. The dielectric properties of the 0-3 PMNT-PC composites are measured as function of both room temperatures and frequency. The composites were pressed together and cured in 98%RH curing chamber for 3 days before measurements. The results indicate that the dielectric properties of the PMNT-PC composites increased with increasing PMNT content with dielectric constant, r obtained for the composites with 0.3, 0.5 and 0.7PMNT with dielectric constant, r values of a 136, 414 and 647 respectively.