xPbTiO3 Single Crystals Research Articles

Novel Piezo-active 2–1–2 Composites with Sets of Large Hydrostatic Parameters

A 2–1–2 composite with two single-crystal components is studied for the first time to highlight large hydrostatic piezoelectric coefficients dh * and gh *, figure of merit dh *gh *, and electromechanical coupling factor kh *. Each 2–1–2 composite contains layers of domain-engineered [011]-poled relaxor-ferroelectric (1–x)Pb(Zn1/3Nb2/3)O3 – xPbTiO3 single crystal (x = 0.0475–0.09) and heterogeneous layers being systems of aligned piezoelectric Li2B4O7 single crystal rods in polyethylene, and these rods have an elliptic cylindrical shape. New diagrams show the volume-fraction ranges wherein large values of dh *> 10−9 C/N, dh *gh *> 2.10−10 Pa−1 and kh *≈ 0.5–0.6 are observed.

Depolarization field in relaxor-based ferroelectric single crystals under one-cycle bipolar pulse drive**Project supported by the National Natural Science Foundation of China (Grant No. 11674270), the Fundamental Research Funds for Xiamen University, China (Grant No. 20720180113), the Education and Scientific Research Project for Young and Middle-aged Teachers of Fujian Province, China (Grant No. JAT170036), the Opening Fund of Acoustics Science and

The [001]c-polarized (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN−PT) single crystals are widely used in ultrasonic detection transducers and underwater acoustic sensors. However, the relatively small coercive field (∼ 2 kV/cm) of such crystals restricts their application at high frequencies because the driving field will exceed the coercive field. The depolarization field can be considerably larger in an antiparallel direction than in a parallel direction with respect to polarization when the bipolar driving cycle starts. Thus, if the direction of the sine wave signal in the first half cycle is opposite to the polarization direction, then the depolarized domains can be repolarized in the second half of the sine cycle. However, if the direction of the sine wave signal in the first half of the cycle is along the polarization direction, then the change is negligible, and the domains switched in the second half of the sine cycle cannot be recovered. The design of electric driving method needs to allow the use of a large applied field to emit strong enough signals and produce good images. This phenomenon combined with the coercive field increases with the driving frequency, thereby making the PMN−PT single crystals usable for high-frequency applications. As such, the applied field can be considerably larger than the conventionally defined coercive field.

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.

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.

Linear optical properties and second-harmonic generation of (1-x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 single crystals

Transmission spectrum and refractive index of (1−x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN-xPT) single crystals were studied and second-harmonic generation signal of the crystal powder was measured in order to characterize the nonlinear optical properties of the crystals. The poling procedure led to increase in the optical transmittance in visible spectral region. PMN-xPT single crystals were optically negative and the refractive index increased with PT concentration. Moreover, PMN-xPT crystals proved to have high nonlinear optical properties and the second-harmonic generation signal measured in powder of PMN-0.39PT crystal was greater than that of KH2PO4, KTiOPO4, and LiNbO3.

Electric field effect of relaxor ferroelectric (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 crystals near morphotropic phase boundary composition probed by Brillouin scattering

The relaxor ferroelectric (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (x = 0.30, PMN–30PT) single crystal was studied under the zero field and the externally applied dc electric field by using micro-Brillouin scattering and dielectric spectroscopies over a wide temperature range of 303–773 K. The noticeable thermal hysteresis of longitudinal acoustic (LA) shift (νB) was observed between zero field heating and zero field cooling processes. Under the electric field of 0.5 kV/cm along the [001] axis, the LA mode splitting was observed in νB due to the coexistence of ferroelectric macrodomain and nanodomain states caused by the random field, and in dielectric measurements the monoclinic (M) and tetragonal phases were appeared between rhombohedral and cubic phases. The LA mode splitting and M phase disappeared under the field of 1.0 kV/cm. The electric field dependence of LA velocity was studied at 304 K. The critical end point of the PMN–30PT single crystal was investigated.

Morphotropic domain structures and dielectric relaxation in piezo-/ferroelectric Pb(In1/2Nb1/2)O3–Pb(Zn1/3Nb2/3)O3–PbTiO3 single crystals

The domain structures, phase transitions and dielectric relaxation of relaxor-based piezo-/ferroelectric (1−x)Pb(In1/2Nb1/2)O3−0.33Pb(Zn1/3Nb2/3)O3−xPbTiO3 (x=0.30, 0.34, 0.37, and 0.42) single crystals, abbreviated as PIN–PZN–PT, grown by flux method, have been analyzed by polarized light microscope and dielectric spectroscopy. The dielectric relaxation was described by the Curie–Weiss law and Lorentz-type quadratic equation. The substitution of Ti4+ ions for the B-site complex (Zn1/3Nb2/3)4+ and (In1/2Nb1/2)4+ ions results in a long-range symmetry breaking, as revealed by the formation of birefringent domains. Single crystal of PIN–PZN–PT with morphotropic compositions exhibit complex domain structures, which are composed of both rhombohedral and tetragonal phases intimately mixed together. The domain structures, the sequence and temperature of phase transitions have been interpreted in relation to the morphotropic phase boundary behavior of the PIN–PZN–PT system. The analysis of morphotropic domain structures and phase transitions provides a better understanding of the microscopic mechanisms of the enhanced piezoelectric properties recently disclosed in the PIN–PZN–PT and other PZN-based piezocrystals.

Kinetics of the phase transition in crystals PbIn1/2Nb1/2O3–PbMg1/3Nb2/3O3–x PbTiO3

The time dependences of the optical transmission, velocity of sound, and elastic constants at room temperature in a number of the [001]-oriented PbIn1/2Nb1/2O3–PbMg1/3Nb2/3O3–xPbTiO3 single crystals with the compositions lying both far from the morphotropic phase boundary and in its vicinity have been investigated. The analysis of the data obtained has been carried out. It has been shown that, in all the studied crystals, phase transitions induced by an electric field occur in two stages: the first stage is an incubation period associated with a small increase in the polarization of a part of the sample being in the glass phase, and the second phase (after the incubation period τ) is a rapid increase in the polarization and the formation of a long-range order. It has been found that the time τ depends on how close is the temperature of measurements to the Vogel–Fulcher temperature Tf. The closer is the temperature of measurements to the Vogel–Fulcher temperature Tf, the weaker is the electric field required to be applied to the sample in order to induce a ferroelectric phase. It has been demonstrated that the phase state of the studied crystals is unstable, which manifests itself in a strong dependence of the incubation period τ on the time between the annealing of the sample and the beginning of the measurements. The stability of the phase state depends on the PbTiO3 concentration: an increase in the concentration leads to a significant increase in the stability.

Composition Dependence of Electrocaloric Effect in (1 − x)Pb(Mg1/3Nb2/3)O3 −xPbTiO3 Single Crystals* *Supported by the State Key Program of National Natural Science of China under Grant No. 51335002, Changzhou Science and Technology Project under Grant No. CJ20130022, and the Priority Academic Program Development of Jiangsu Higher Education Institutions on Renewable Energy Material Science and Engineering

Composition dependence of electrocaloric effect is investigated in (1 − x)Pb(Mg1/3Nb2/3)O3 − xPbTiO3 single crystals by using an eighth-order Landau–Devonshire theory. The applied electric field along [001] direction reduces the ferroelectric-ferroelectric phase transition temperatures, but increases the Curie temperatures. The electrocaloric coefficients of tetragonal phase are much larger than that of rhombohedral and monoclinic phase. A negative electrocaloric effect is observed near the MC–T phase transition in 0.69Pb(Mg1/3Nb2/3)O3–0.31PbTiO3 single crystal. The application of a strong enough electric field results in a high adiabatic temperature change over a broad range of temperature. Therefore, it would be useful to construct a solid state cooling cycle over a broad temperature range for practical applications.

Piezoelectric and electro optic properties of tetragonal (1 − x)Pb(Mg1/3Nb2/3)O3−xPbTiO3 single crystals by phenomenological theory**Project supported by the National Natural Science Foundation of China (Grant No. 51335002), the Changzhou Science and Technology Project, China (Grant No. CJ20130022), and the Priority Academic Program Development of Jiangsu Higher Education Institutions, China.

An eighth-order Landau–Devonshire theory is constructed to investigate the piezoelectric and electro–optic properties of tetragonal (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 single crystals (x = 0.38 and x = 0.4). The dielectric stiffness coefficients of the Landau potential are obtained by fitting to the dielectric properties and the phase transition temperature between cubic phase and tetragonal phase. It is indicated that tetragonal (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 single crystals have the first-order cubic-tetragonal phase transitions. The dielectric constants are in great agreement with the experimental results. The piezoelectric coefficients d33 and d31 at room temperature are about 145 pC/N and −62 pC/N respectively which are smaller than that of (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 single crystals around the morphotropic phase boundary. Moreover, tetragonal (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 single crystals have the linear electro–optic coefficients rc = 33.7 pm/V and rc = 28.8 pm/V for x = 0.38 and x = 0.4, respectively which are in accordance with the measurements.

Phase diagram of (1−x)PbMg1/3Nb2/3O3−xPbTiO3 single crystals

Experimental results indicated that the Rhombohedral (R) phase, Tetragonal (T) phase, Cubic (C) phase, and the Monoclinic (MC) phase are the stable phases in ferroelectric (1−x)PbMg1/3Nb2/3O3−xPbTiO3 single crystals. The Monoclinic MC phase, around the morphotropic phase boundary, was observed in a composition region (0.31 &amp;lt; x &amp;lt; 0.37) between the rhombohedral and tetragonal phase. However, the recent theory poses a challenge in explaining the “temperature–composition” phase diagram completely. Here, an eighth-order expansion of Landau-Dovenshire theory is constructed to investigate the phase transition properties of (1−x)PbMg1/3Nb2/3O3−xPbTiO3 single crystals. A full phase diagram is obtained in phenomenological parameter space which is in good accordance with experimental observation. The ferroelectric, dielectric, and piezoelectric properties are calculated in (1−x)PbMg1/3Nb2/3O3−xPbTiO3 single crystals with different compositions.

Anomalous variations in elastic properties of lead zirconate niobate-lead titanate single crystals in the vicinity of its ferroelectric phase transition

The acoustic phonon mode anomalies in the paraelectric phase of tetragonal and rhombohedral (1 − x)Pb(Zn1/3Nb2/3)O3−xPbTiO3 single crystals were systematically investigated by Brillouin light scattering measurements. The inverse relaxation time in the paraelectric phase of both crystals showed a stretched-type slowing-down temperature dependence approaching the structural phase transition temperature instead of a normal critical slowing-down. The observed anomalous part of the elastic constant in the paraelectric phase of the tetragonal crystal in the vicinity of , exhibited a -type dependence in the temperature range from to . On the other hand, the elastic constant of the rhombohedral ferroelectric crystal exhibited a deviation from such a temperature dependence. This was attributed to the interaction of acoustic phonon modes with strong polarization fluctuations and elastic deformation arising from the complex dynamics of polar nanoregions.

Microstructure and dielectric relaxation of dipolar defects in Mn-doped (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 single crystals

The atomic-scale defect structures in Mn-doped (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMNT) single crystal have been investigated by using X-ray absorption fine structure analysis. Temperature-dependent diffusive dielectric loss peaks as a doping effect were found for Mn-doped PMNT. Combined with these experiments the structure of dipolar defects was confirmed. There is an oxygen vacancy around Mn2+ ions, and vacancy and ion interact strongly to form the charge-dipole [(MnTi2+)″-VO]. The dipolar defects will pin the domain walls, thereby reducing the dielectric loss of the crystals.

Macroscopic and local piezoelectric properties of Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals exhibiting giant piezoelectric response

The temperature and bias field dependences of macroscopic, measured by pulsating load method, and local, measured by piezoresponse force microscopy, longitudinal piezoelectric responses have been studied in (001)-oriented flux-grown (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (0.0 ≤ x ≤ 0.29) single crystals. Both types of responses exhibit a dramatic enhancement with increasing bias fields. At the same time, their temperature maxima shift from the Vogel-Fulcher temperature to the vicinity of the dielectric permittivity maximum, where the critical point in the E-T phase diagram is located. Both datasets confirm a quasicritical nature of the giant field-induced piezoelectric response in relaxor single crystals.

Piezoresponse force microscopic study of ferroelectric (1 − x)Pb(Sc1/2Nb1/2)O3 − xPbTiO3 and Pb(Sc1/2Nb1/2)O3 single crystals

The microscopic piezoelectric response and ferroelectric domain switching in the (001)-oriented rhombohedral piezo-/ferroelectric (1 − x)Pb(Sc1/2Nb1/2)O3 − xPbTiO3 (PSN-PT) and relaxor Pb(Sc1/2Nb1/2)O3 (PSN) single crystals were studied by piezoresponse force microscopy. PSN-PT shows clear domain structures while the domain contrast of PSN is very weak. For PSN-PT, after being fully poled vertically, its lateral domain structure is still composed of a multi-domain state. Both PSN-PT and PSN crystals respond to positive and negative DC field drives through piezoelectricity. However, their poling behaviors are different. For PSN-PT, during successive applications of a positive external electric field, the areas with piezoresponse in phase with the electric field grow at the expense of domains of opposite piezoresponse, implying a domain switching process via sideway motion of domain walls. On the other hand, in the PSN single crystal, the piezoresponse contrast of the alternatively poled area shows a uniformly fading and enhancing pattern, depending on the direction of the polarization component of the domains relative to the external field. While the domain pattern of PSN-PT and its evolution under an external field behave like a normal ferroelectric material, the domain structure and domain evolution process of PSN appear to be abnormal for a ferroelectric, but consistent with the character of a relaxor.

Effective electro‐optic coefficient of (1–x)Pb(Zn1/3Nb2/3)O3–xPbTiO3 single crystals

AbstractRefractive indices and effective electro‐optic coefficient γc of (1–x)Pb(Zn1/3Nb2/3)O3–xPbTiO3 (PZN‐xPT, x = 0.05, 0.09 and 0.12) single crystals were measured at 532 nm wavelength. Orientation and temperature dependences of the electro‐optic coefficient were investigated. Large electro‐optic coefficient (γc = 470 pm/V) was observed in [001]‐poled PZN‐0.09PT crystal. More importantly, γc of tetragonal PZN‐0.12PT is almost unchanged in a temperature range −20 ∼ 80 °C. The γc of PZN‐xPT single crystals are much higher than that of widely used electro‐optic crystal LiNbO3 (γc = 20 pm/V). These results show that PZN‐xPT single crystals are very promising materials for electro‐optic modulators in optical communications.

Stability of tetragonal 〈0 0 1〉 oriented PZN-12PT single crystals

The present paper reports on the synthesis and electromechanical characterization of tetragonal (1−x)Pb(Zn1/3–Nb2/3)O3–xPbTiO3 (x=12) single crystals as a function of various external disturbances. Tetragonal PZN-12PT single crystals were grown using the flux method. The set of piezoelectric coefficients in the lateral mode was measured. Samples with size of 10×2×1mm3 were polled in the 〈001〉 and 〈110〉 crystallographic directions and were found to possess a high Curie temperature (>170°C). Moreover, no ferroelectric–ferroelectric phase transition was observed for the positive temperatures, which expanded the usage range significantly. Tetragonal crystals were also found to have high coercive field, mechanical quality factors, and good optical properties, attracting much effort on the characterization of tetragonal PZN-12PT crystals. However, the most interesting properties in the lateral mode were obtained for 〈001〉. Finally, the thermal stability and stress dependence were studied in order to determine the working conditions.

Role of Single-Crystal Pillars in Forming the Effective Properties and Figures of Merit of Novel 1–3 Piezocomposites

This work examines the modelling and potential formation of submicron ferroelectric pillars which are exploited as an active component of modern 1–3 piezocomposites. These structures are of interest in sensor and actuator technologies, and most notably energy harvesting devices. This research area has seen recent growth in terms of interest with the advent of electronics with greater portability and wireless sensors. The fabrication of nanopillars on the single crystal surface is investigated using a nanoimprint lithography (NIL) approach. The use of a disposable master allows the user to reproduce large-area nanostructures and dry etching then allows for the nanopillars to be formed. Results on the prediction of effective electromechanical properties of 1–3-type composites either LiNbO3 single crystal or (1 – x)Pb(Mg1/3Nb2/3)O3 – xPbTiO3 (PMN-PT) single crystal are given for comparison.

Design of Readout Circuit for Pyroelectric Detector Based on Novel Pyroelectric Materials

Recently, scientists discovered that relaxor-based ferroelectric single crystals, such as (1-x)Pb(Mg1/3Nb2/3)O3 -xPbTiO3 (PMN-xPT, or PMNT) single crystals, exhibit extra-high pyroelectric responses. They are promising candidates for optical power detectors in broad bandwidth at ultraviolet, visible and infrared wavelength.To fabricate high performance infrared detectors with relaxor-based single crystals, the related readout circuit was investigated to increase signal-to-noise ratio, and 8×1 CMOS readout circuit is fabricated to gain very weak current, which provides a solution for uncooled large focal plane arrays devices based on relaxor-based single crystals.

Signal readout for pyroelectric detector based on relaxor ferroelectric single crystals

AbstractRelaxor‐based ferroelectric single crystals, such as (1 − x)Pb(Mg1/3Nb2/3)O3xPbTiO3 (PMNxPT, or PMNT) single crystals, exhibit large pyroelectric response, low thermal diffusivity, and high temperature stability. To fabricate high performance infrared detectors with relaxor‐based single crystals, the related readout circuit was investigated to increase signal‐to‐noise ratio, and 8 × 1 CMOS readout circuit is fabricated to gain very weak current, which provides a solution for uncooled large focal plane arrays devices based on relaxor‐based single crystals.