PZT System Research Articles

Domain evolution ofBaTiO3ultrathin films under an electric field: A first-principles study

A first-principles-derived method is used to study the morphology and electric-field-induced evolution of stripe nanodomains in (001) BaTiO3 (BTO) ultrathin films, and to compare them with those in (001) Pb(Zr,Ti)O3 (PZT) ultrathin films. The BaTiO3 systems exhibit 180o periodic stripe domains at null electric field, as in PZT ultrathin films. However, the stripes alternate along [1-10] in BTO systems versus [010] in PZT systems, and no in-plane surface dipoles occur in BTO ultrathin films (unlike in PZT materials). Moreover, the evolution of the 180o stripe domains in the BaTiO3 systems, when applying and increasing an electric field along [001], involves four regions: Region I for which the magnitude of the down dipoles (i.e., those that are antiparallel to the electric field) is reduced, while the domain walls do not move; Region II in which some local down dipoles adjacent to domain walls switch their direction, resulting in zigzagged domain walls - with the overall stripe periodicity being unchanged; Region III in which nanobubbles are created, then contract along [110] and finally collapse; and Region IV which is associated with a single monodomain. Such evolution differs from that of PZT ultrathin films for which neither Region I nor zigzagged domain walls exist, and for which the bubbles contract along [100]. Discussion about such differences is provided.

The nature and phase transition F RL–F RH in PZT doped with Nb

In the composition region of PZT rich in zirconium, (0.05 < x < 0.35) there are two phase transitions. The first takes place between the high and low temperature Rhombohedric phases F RL–F RH both of which are ferroelectric, and the second between the high-temperature ferroelectric Rhombohedric phase and the cubic phase which is paraelectric (F RH–PE). The phase F RL–F RH transition of the PZT system has been studies using different methods. In all of the cases, the fundamental difficulty in establishing the transition characteristics has been the small alteration in the electrical parameters of this transition. In this work, we have verified, when the samples being studied are polarized, the changes are intensified significantly, undoubtedly allowing both the characterization of the transition temperature and its nature. In order to carry out our study, we have selected several PZT compositions doped with niobium, by moving the Zr/(Ti + Nb) > 90/10 region, in which we have determined the characteristics of the transition phase and the influence of niobium on it.

Na/K 비 변화에 따른 무연 [Li0.04(NayK1-y)0.96](Nb0.86Ta0.1Sb0.04)O3세라믹스의 압전 및 유전특성

In this paper, lead-free [<TEX>$Li_{0.04}(Na_{y}K_{1-y})_{0.96}](Nb_{0.86}Ta_{0.1}Sb_{0.04})O_{3}$</TEX> (y=0.4 - 0.58) ceramics were manufactured using conventional miked oxide method for acoustic emission(AE) sensor application and their dielectric and piezoelectric properties were investigated with the variations of Na/K ratio. The samples in the composition Na/K=54/46 exhibited excellent electrical properties of <TEX>$d_{33}=300$</TEX> PC/N and kp=0.49. Taking into consideration above piezoelectric properties, it can be concluded that the [<TEX>$Li_{0.04}(Na_{y}K_{1-y})_{0.96}](Nb_{0.86}Ta_{0.1}Sb_{0.04})O_{3}$</TEX> system ceramics are the promising lead-free materials capable of substituting PZT system ceramics.

Computational investigation of B-site donor doping effect on fatigue behavior of lead zirconate titanate

The effect of the B-site donor on the fatigue behavior of lead zirconate titanate (PZT) was studied. Seven elements were considered. The formation energies of oxygen vacancies and band structures of these doped systems were investigated. It was found that the Nb, Ta, and W doped PZT systems have the highest formation energy of oxygen vacancies as well as reduced occupations of Ti 3d states by the electrons released from oxygen vacancies. Therefore, the systems respectively doped with Nb, Ta, and W can effectively improve the fatigue property of PZT.

Ferroelectric and piezoelectric properties of Ba modified lead zirconium titanate ceramics

Ferroelectric and piezoelectric properties of Pb1−xBax(Zr0.532Ti0.468)O3 ceramic compositions for x = 0 to 40 mole% were investigated. As Ba concentration increased, the microstructural studies revealed that grain growth was inhibited and apparent density decreased in PZT ceramics. The room temperature dielectric response (εRT) increased up to 30 mole% with low values of dielectric loss (tan δ). The ferroelectric properties (Pr, Ps and Ec) have shown a decreasing trend as Ba concentration increased from 0 to 40 mole% in the PZT system. The optimum piezoelectric charge coefficient (d33 = 473 pC N−1), piezoelectric planar coupling coefficient (kp = 0.584) and piezoelectric thickness coupling coefficient (kt = 0.408) were found in 30 mole% Ba composition, respectively.

High‐Energy Density Ceramic Composition in the System Pb(Zr,Ti)O3–Pb[(Zn,Ni)1/3Nb2/3]O3

This study reports a high‐energy density piezoelectric polycrystalline ceramic composition in the system Pb(Zr1−xTix)O3–Pb[(Zn1−yNiy)1/3Nb2/3]O3 (PZT–PZNN). Two different Zr/Ti ratios in the PZT system were investigated: 52/48 corresponding to morphotropic phase boundary (MPB) and 56/44 corresponding to the tetragonal phase. The compositions investigated in this study are represented as: 0.9Pb(Zr0.52Ti0.48)O3–0.1Pb(Zn1/3Nb2/3)O3 [0.9PZT (52:48)–0.1PZN]+y wt% MnCO3, where y varies from 0 to 0.9 wt% and 0.9Pb(Zr0.56Ti0.44)O3–0.1Pb[(Zn0.8Ni0.2)1/3Nb2/3]O3 [0.9PZT (56:44)–0.1PZNN] +y mol% MnO2, where y varies from 1 to 3 mol%. A high‐energy density material is characterized by the large magnitude of the product of the piezoelectric voltage constant (g) and the piezoelectric strain constant (d) given as (dg). The condition for obtaining large magnitude of dg was derived to be as |d|=ɛn, where ɛ is the permittivity of the material and n is a material constant having a lower limit of 0.5. The d33.g33 value of the samples having composition 0.9 PZT (56:44)–0.1 PZNN+2 mol% MnO2 (sintered in two steps at 1100°–1000°C) was found to be 18456.2 × 10−15 m2/N, which, to the knowledge of the authors, is the highest value reported for polycrystalline ceramics. This composition was also found to exhibit a high magnitude of g33 as 83.1 V·(m·N)−1, corresponding to the magnitude of n as 1.126.

Dielectric relaxation behavior inPb(Mn1/3Sb2/3)O3–Pb(Zr,Ti)O3 systems

A study of the relaxor behavior ofxPb(Mn1/3Sb2/3)O3–(1−x)Pb(Zr0.52Ti0.48)O3 (PMS–PZT) (x = 0.05–0.15) ceramics is presented. X-ray diffraction (XRD) showed that all samples displayed asingle-phase perovskite structure. Two mechanisms might explain the relaxor behavior inxPMS–(1−x)PZT systems. One is attributed to the inhomogeneous distribution of B sites in theABO3 perovskite structure and the other is attributed to the defect relaxation related to oxygenvacancies. The electric conductivity of PMS–PZT ceramics increased with the increase ofPMS content, indicating that the concentration of carriers increased with the increase indoping content. Annealing the as-sintered PMS–PZT ceramics under oxygen atmospheresignificantly lowered their DC conductivities. This phenomenon was attributed to thereduction of oxygen-vacancy concentration.

Temperature effect in thermosonic wire bonding

The temperature effect on bonding strength and ultrasonic transmission in a PZT transducer system was investigated. The results show that, the temperature change influences the material features of the bonding interface, such as elastic modulus, tensile strength of gold ball and Ag substrate, which results in different bonding strengths. Moreover, the temperature change also influences the impedance and dissipative ultrasonic energy in the PZT system. The current signal of PZT transducer was analyzed by join time-frequency analysis, which can reveal the current change in a bonding process more clearly and completely. The analysis shows that the bonding parameters influence mutually. These results can help build some criteria for parameter match and optimization in wire bonding processes.

Compositional Dependence of Piezoelectric Properties in NaxK1−xNbO3 Lead‐Free Ceramics Prepared by Spark Plasma Sintering

Lead‐free piezoelectric NaxK1−xNbO3 (x=20–80 mol%) ceramics were fabricated using spark plasma sintering at a low temperature (920°C). All the NaxK1−xNbO3 ceramics showed a similar orthorhombic phase structure, while the corresponding lattice parameters decreased from the KNbO3 side to the NaNbO3 side with increasing Na content. A discontinuous change in lattice parameter close to composition of 60 mol% Na indicated the presence of a transitional area that is similar to the morphotropic phase boundary (MPB) in NaxK1−xNbO3 ceramics. The sintered density of the NaxK1−xNbO3 ceramics decreased with increasing Na content, from a relative density of 99% for the K‐rich side to 92% for the Na‐rich side. The piezoelectric constant d33 and planar mode electromechanical coupling coefficient kp showed a maximum value of 148 pC/N and 38.9%, respectively, due to the similar MPB effects in the PZT system.

Effects of excess ZnO addition on La-doped PZN–PZT ceramics prepared by hot pressing

Effects of excess ZnO addition on phase structure, dielectric and piezoelectric properties in La-doped Lead zinc niobate, Pb(Zn 1/3Nb 2/3)O 3 (PZN)–PZT systems have been investigated. Addition of excess ZnO helps to suppress the formation of the pyrochlore phase. Microstructure revealed the grains size to decrease with excess ZnO addition. Enhanced T max and d 33, and reduced ɛ max and Tan δ were observed. Adding proper excess ZnO in La-like doped PZN-based systems seems an effective approach to suppress the formation of the pyrochlore phase, enhance piezoelectric constant d 33 and reduce dielectric loss.

Effects of La&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; on the Piezoelectric Properties of Lead-Free (Bi&lt;sub&gt;0.5&lt;/sub&gt;Na&lt;sub&gt;0.5&lt;/sub&gt;)&lt;sub&gt;0.94&lt;/sub&gt;Ba&lt;sub&gt;0.06&lt;/sub&gt;TiO&lt;sub&gt;3&lt;/sub&gt; Piezoelectric Ceramics

In an approach to acclimate ourselves to the recent ecological consciousness trends, a lead free piezoelectric material, bismuth sodium barium titanate (Bi0.5Na0.5)0.94Ba0.06TiO3 (BNBT), was considered as an environment-friendly alternative to the PZT system. A perovskite BNBT was synthesized by the conventional bulk ceramic processing technique.La2O3 as a dopant was incorporated into the BNBT system up to 0.025 mol, and the doping effects on subsequent piezoelectric and dielectric properties were systematically investigated. In the case of La2O3 addition, the formation of grain boundary coherency was remarkably increased, and the sintered density was increased with increasing La2O3 contents. Piezoelectric and dielectric properties were shown to have the maximum value at 0.02 mol of La2O3 addition. La3+ ions were believed to act as a softener in the BNBT system and to enhance dielectric and piezoelectric properties in this study.

Synthesis, structural and electrical properties of La modified PZT system

Lead zirconate titanate (PZT) ceramics with Zr/Ti (70:30) have been synthesized with the substitution of (8, 10 and 12 mole%) of La. Polycrystalline samples were prepared by high temperature solid-state reaction technique. XRD study reveals the formation of single-phase perovskite structure for all the compositions. There is a transformation in crystal structure observed from tetragonal to co-existence of tetragonal and orthorhombic to single orthorhombic phase with the increase in lanthanum concentration in the basic PZT composition. Detailed dielectric study has been performed and results indicate the shift in transition temperature from lower to the higher side. Ferroelectric hysteresis behaviour was also studied as a function of applied electric field for all the three compositions. Slimming behaviour of the loops was found with the increase in La concentration, which may be attributed to the tendency towards the antiferroelectric nature of the material.

Thermodynamic Assessment of the PZT System

The thermodynamic assessment of the PZT system is carried out by the CALPHAD method. The thermodynamic properties of the phases are described using compound energy formalism (CEF) for the various solid phases and a solution model for the liquid. Three boundary systems PbO-ZrO 2 , PbO-TiO 2 and ZrO 2 -TiO 2 are reassessed based on the most recent experimental data, while the ternary PbO-TiO 2 -ZrO 2 system is modelled for the first time. Calculated phase diagrams are compared with the experimental data.

Effects of uniaxial stress on dielectric properties of ferroelectric ceramics

The effects of uniaxial stress on the dielectric properties of ceramics in PMN–PZT system are investigated. Ceramics with the formula ( x )Pb(Mg 1/3 Nb 2/3 )O 3 –(1 − x )Pb(Zr 0.52 Ti 0.48 )O 3 when x = 0.0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1.0 are prepared by a conventional mixed-oxides method. The sintered ceramics are perovskite materials with their physical properties proportionally depending on the PMN and PZT contents. The dielectric properties under the uniaxial stress of the unpoled and poled PMN–PZT ceramics are observed at stress levels up to 5 MPa. For the unpoled ceramics, the dielectric properties do not change significantly with the applied stress and the changes are independent of the ceramic compositions. For the poled ceramics, on the other hand, the dielectric constant of the PZT-rich compositions increases slightly, while that of the PMN-rich compositions decreases with increasing applied stress. In addition, changes in the dielectric loss tangent with stress are found to be composition independent. This study clearly shows the influences of the domain re-orientation, domain wall motion, degradation and depoling mechanisms on the variation of the dielectric properties of PMN–PZT ceramics under the uniaxial stress.

Phase formation and transitions in the lead magnesium niobate–lead zirconate titanate system

Abstract The phase formation and transition mechanism of perovskite ceramics in the (1 − x )Pb(Mg 0.33 Nb 0.66 )O 3 – x Pb(Zr 0.52 Ti 0.48 )O 3 , (1 − x )PMN– x PZT system prepared by a modified mixed-oxide synthetic route have been investigated for various chemical compositions and firing temperatures. Lattice parameter changes were examined as a function of composition. It is seen that perovskite phases undergo the transitions (pseudo)cubic to tetragonal in the x value range 0.0–1.0. The degree of tetragonality and average lattice parameters were found to increase with PZT content across the whole solid solution range.

Improving ferroelectric properties of Pb(Zr 0.44Ti 0.56)O 3 ceramics by Pb(Mg 1/3Nb 2/3)O 3 addition

Ceramics in PMN–PZT system with formula ( x)Pb(Mg 1/3Nb 2/3)O 3–(1 − x)Pb(Zr 0.44Ti 0.56)O 3 (when x = 0.0, 0.1, 0.3, 0.5, 0.7) are prepared by a solid-state mixed-oxide technique. The phase formation behavior and microstructure are studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The ferroelectric properties are measured by a simple Sawyer–Tower circuit. XRD analysis shows that the possible morphotropic phase boundary (MPB) between the tetragonal and pseudo-cubic phases is identified near the 0.3PMN–0.7PZT composition. In addition, ferroelectric properties of PMN–PZT ceramics are found to enhance at the ceramic composition with x = 0.3. This clearly implies that the MPB of this PMN–PZT system lies near the x = 0.3 composition. Most importantly, this study shows that the addition of PMN can improve the ferroelectric behavior in PZT ceramics.

Effects of La2O3 on the Piezoelectric Properties of Lead-Free (Bi0.5Na0.5)0.94Ba0.06TiO3 Piezoelectric Ceramics

【A lead free piezoelectric material, bismuth sodium barium titanate $(Bi_{0.5}Na_{0.5})_{0.94}Ba_{0.06}TiO_3$ (BNBT), was considered as an environment-friendly alternatives for the current PZT system. A perovskite BNBT was synthesized by conventional bulk ceramic processing technique. In order to improve piezoelectric properties, $La_2O_3$ as a dopant was incorporated into the BNBT system up to 0.025 moi, ana the effects on subsequent the piezoelectric ana dielectric properties were systematically investigated. With increasing $La_2O_3$ contents, the equilibrium grain shape was remarkably evidenced and sintered density was increased. Piezoelectric and dielectric properties were s]town to have maximum values at the $La_2O_3$ contents of 0.02 mol. $La^{3+}$ ions seemed to act as a softener in the BNBT system and to enhance dielectric and piezoelectric properties in this study. ဤΗ⨀ ሀ老 ? ??邰ʗ⨀ 塨岖⨀ ⁗잖⨀ 頨Ζ⨀ 餂 ?돐 련Η⨀ 䞖⨀ ／ࠀ‮Η⨀ 夂 ?? 䠀 က ᠀ � ??邰ʗ⨀ 適岖⨀ 適?⨀ �Ζ⨀  ?돐 硙잖⨀ 硙䞖⨀ ᠦΗ⨀ ? ?? ⠦Ζ⨀ ? ꠉ Ā᭢合 㔀܀檘 큭ࠁ琇؀ ᭢合 Ā Ā Ā ? � 倦Ζ⨀ ਀ 倦Ζ⨀ 性Ζ⨀ ؀က 性Ζ⨀ 怦Ζ⨀ 搀 怦Ζ⨀】

Excess ZnO Addition in Pure and La‐Doped PZN–PZT Ceramics

The effects of excess ZnO addition on phase structure, dielectric and piezoelectric properties in pure and La‐doped lead zinc nicobate (PZN)—lead zirconate titanate (PZT) systems have been investigated. Addition of excess ZnO helps suppress and prevents the formation of pyrochlore phase for both systems. However, the effects on electrical properties in the systems were very different, even opposite. For the PZN–PZT system, excess ions possibly exist as second‐phase inclusion particles. Based on Raman spectra and the changes in properties, in the La‐doped PZN–PZT system, excess ions are very likely to enter A‐site lead vacancies. Adding proper excess ZnO in La‐like‐doped PZN‐based systems is an effective approach to achieve a pure perovskite phase, enhanced piezoelectric constant d33, and reduced dielectric loss.

SWITCHING INDUCED ELECTROLUMINESCENCE IN PZT CERAMICS IN HIGH-VOLTAGE PULSE FIELD†

ABSTRACT The luminescence features and internal electronic screening in the ferroelectrics ceramics of PZT system at superfast switching in fast-rising pulse fields are investigated. †Originally presented at 10th European Meeting on Ferroelectricity, Cambridge, UK, August 3–8, 2003.

Factors Determining Grain Orientation in Bismuth Sodium Potassium Titanate-Lead Zirconate Titanate Solid Solutions Made by the Reactive Templated Grain Growth Method

Grain-oriented Bi0.5(Na0.85K0.15)0.5TiO3-Pb(Zr1−xTix)O3 (BNKT-PZT) ceramics were prepared via the reactive templated grain growth method, using platelike Bi4Ti3O12 particles. Factors that determine the degree of orientation were examined. Prereacted PZT gave a larger degree of orientation than PZT raw materials (PbO, ZrO2, and TiO2) in the 75BNKT-25PZT (x= 0.5) system. Increases in the titanium concentration in the PZT of the 75BNKT-25PZT system and in the BNKT concentration in the yBNKT-(100 −y)PZT (x= 0.5) system increased the degree of orientation. The direction of material transport between BNKT and PZT was important to obtain ceramics with a large degree of orientation.