Stability of Fe3+ — VO defect pairs in polycrystalline Pb(Ti,Zr)O3

The intensity of the EPR signal with g = 5.985 arising from a ferric ion — oxygen vacancy defect pair (Fe³⁺ — V_O) in PbTiO₃, varies with the extent of PbO nonstoichiometry at constant Fe³⁺ content due to an increased oxygen vacancy concentration. In PZT solid solutions, the signal intensity decreases with an increase in Zr. A lower intensity is also noticed for Fe³⁺ — V_O signals in PbZrO₃. This behaviour is explained on the basis of PbO nonstoichiometry arising from independent Pb- and O-vacancies as well as the randomly distributed crystallographic shear (CS) plane defects. The contribution to PbO nonstoichiometry from CS planes is larger in high zirconium compositions of PZT.     

Conduction at domain walls in insulating Pb(Zr0.2 Ti0.8)O3 thin films

Domain wall conduction in insulating Pb(Zr(0.2) Ti(0.8))O(3) thin films is demonstrated. The observed electrical conduction currents can be clearly differentiated from displacement currents associated with ferroelectric polarization switching. The domain wall conduction, nonlinear and highly asymmetric due to the specific local probe measurement geometry, shows thermal activation at high temperatures, and high stability over time.     

Pb(Zr0.5, Ti0.5)O3 nanofibres by electrospinning

Lead zirconate titanate Pb(Zr_0.5, Ti_0.5)O₃ nanofibres with diameters ranging from 200–300 nm have been synthesized by calcination of the electrospun lead zirconate titanate/polyvinyl acetate composite fibres. The morphology and crystalline phase features of these lead zirconate titanate (PZT) nanofibres have been studied by various physico-chemical methods such as SEM, AFM, XRD and FT–IR. The formation of perovskite PZT phase was observed at temperatures as low as 550 °C.     

La0.7Sr0.3MnO3-Pb(Zr,Ti)O3双层膜中的磁电(ME)效应

由溶胶-凝胶法制备出锰酸盐La0.7Sr0.3MnO3粉料,经1300K热压并在1573K高温下烧结成块材,并与Pb(Zr,Ti)O3胶合形成弹性耦合双层膜.相较于涂敷膜(tape casting)复合样品,该双层膜显示出更为优良的ME耦合效应.横向耦合要比纵向耦合更为强烈,并当外加磁场为150 Oe时ME电压系数达到峰值.分析表明由磁场和频率变化导致的ME系数变化的实验值与理论值符合的很好.     

紫外脉冲激光淀积法制备Pb(Ta0.05Zr0.48Ti0.47)O3薄膜的铁电性质

用紫外脉冲激光淀积方法在Pt／TiO2／SiO2／Si(001)衬底上制备了La1-xSrxCoO3／Pb(Ta0.05Zr0.48Ti0.47)O3(PTZT)／La1-xSrxCoO3异质结构薄膜。发现底电极La0.25Sr0.75CoO3可以诱导PTZT薄膜沿(001)方向取向生长。在500kHz和5V的工作电压下铁电电容器La0.25Sr0.75CoO3/PTZT／La0.25Sr0.75CoO3经过5×1010次反转之后,仍保持其初始电极化的96％。此异质结构横截面的扫描电镜照片表明界面上没有明显的因化学反应导致的第二相存在。     

Phase evolution of electron-beam evaporated Pb(Zr,Ti)O3 thin films

Solid phase reactions among electron-beam deposited PbO, ZrO₂ and TiO₂ in the thin film state as distinct from those occurring in the bulk state are described under varied annealing conditions leading to growth of perovskite PZT phase. Loss of PbO by direct high temperature (700 °C) anneal led to the growth of cubic A₂B₂O_7−x pyrochlore as well as an AB₃O₇ phase of monoclinic structure. A lower temperature initial anneal at 600 °C in O₂ ambient minimises PbO loss through phase transformation to tetragonal Pb₃O₄ and better crystallised oxide phases partially react to form pyrochlore as well as perovskite PZT. This partial reaction is kinetically driven as it goes to completion in ∼4 h resulting in transformation of pyrochlore to perovskite phase. At high temperature (800 °C) A₂B₂O_7−x phase converts to PZT perovskite and the AB₃O₇ dissociate to yield TiO₂ secondary phase inclusion in the PZT film.     

力电多场鼓包法测定PZT铁电薄膜的横向压电系数

为表征Pb(Zr_(0.52)Ti_(0.48))O_3(PZT)薄膜的横向压电性能,以纯力场鼓包测试模型和铁电薄膜材料压电方程为基础,推导了PZT铁电薄膜的力电耦合鼓包本构模型。采用溶胶-凝胶法制备了PZT铁电薄膜,并通过化学腐蚀法获得PZT薄膜鼓包样品。在外加电压为0~14V的条件下进行鼓包测试。结果表明,在纯力场作用下,PZT薄膜的弹性模量和残余应力分别为91.9GPa和36.2MPa;随着电压从2V变化到14V,PZT薄膜的横向压电系数d31从-28.9pm/V变化到-45.8pm/V。本工作所发展的力电耦合鼓包测试技术及力电耦合鼓包本构模型为评价铁电薄膜材料的横向压电性能提供了一种有效的分析方法。     

Characterization of Pb(Zr,Ti)O3 thin films obtained by MOD

Pb(Zr, Ti)O₃ thin films were deposited by dip-coating on polycrystalline alumina substrates by using an MOD method. The thickness and homogeneity of the films were measured as a function of dip rates and solution concentration. Heating and cooling schedules determined the main structure of the crystallized films. Rheology measurements and Fourier transform-infrared spectra were carried out to obtain a better knowledge of the solution features. A microstructural development study and some ferroelectric measurements were also carried out.     

磁控溅射工艺参数对Pb(Zr,Ti)O3薄膜织构的影响

利用RF磁控溅射法制备了Pb(Zr,Ti)O3(PZT)铁电薄膜,利用X射线衍射(XRD)法研究了薄膜的相组成及溅射工艺参数对薄膜织构的影响.结果表明,在小靶基距时,过高溅射功率不利于获得纯钙钛矿相的PZT铁电薄膜.溅射功率及溅射气压影响PZT薄膜的织构及其织构散漫度,提高溅射气压及溅射功率,(111)织构漫散度随之提高.在靶基距为80mm时,选择150w、0.7Pa的溅射工艺可获得具有最佳(100)织构的PZT薄膜.     

The Pb–Pb and O–Pb Nuclear Spin Coupling in Ba(Pb,Bi)O3 Oxides

We report the ¹⁷O, ²⁰⁷Pb NMR and ¹⁷O–²⁰⁷Pb SEDOR study of superconducting BaPb_1-x Bi _x O₃ (x 0.35) oxides. Inhomogeneous The results points to the formation of microscopically inhomogeneous distribution of the carrier density in metallic phase. The local spin susceptibility is increased around Bi cation within an area, which is delimited by its two first cation shells.     

Preparation of Lanthanum-Doped Pb(Zr,Ti)O3 Ceramics Sheets by Tape Casting

The physical and electrical properties of lanthanum doped Pb（Zr,Ti）O3 ceramic sheets （PLZT） which were prepared by tape casting method were carried out. Tape casting of lanthanum modified PZT was performed using commercial cellulose acetate binders and poly（ethylene glycol） plasticizers in ethanol solvent. Tapes from these slips were casted on a polymer substrate. The PLZT green tapes were stacked for 5 units and sintered in air at 1050℃ for 1 h with heating rate 5℃/min. SEM micrographs show that the tape is dense （90.26% of theoretical density） and rather uniform with grain size of approximately 1.1 9 m. The dielectric permittivity and loss tangent of PLZT ceramics as a function of temperature at 1 kHz suggest that the compounds exhibit a phase transition of diffuse type. The transition temperature （Tm ） and piezoelectric coefficient （ d33 ） were 110℃ and 117 pC/N, respectively.     

Preparation of spherical Pb(Zr,Ti)O3 powders by ultrasonic spray pyrolysis

Spherical Pb(Zr,Ti)O₃ powders were prepared from the aqueous acetate-base solution by ultrasonic spray pyrolysis. The raw materials were Pb(C₂H₃O₂)-3H₂O, ZrO(C₂H₃O₂)₂ and a mixture of Ti(C₃H₇O)₄ and C₅H₇O₂. A single-phase PZT was formed at 900 C in air and at 700 C in O₂ atmosphere. The PbTiO₃ phase, as an intermediate product, was observed in the formation of PZT and no PbZrO₃ phase was detected under our experimental conditions. The intensity of the PbTiO₃ peak decreased with increasing reaction temperature in air, while the reverse effect of reaction temperature was observed in O₂. Spherical and irregular-shaped particles coexisted in the powder containing the minor PbTiO₃ phase, while the particles of a single-phase PZT have spherical morphology with little evidence of irregular-shaped particle formation.     

Orientation control and electrical properties of sputtered Pb(Zr,Ti)O3 films

Relationship between the crystallographic orientation and the electrical properties of the Pb(Zr,Ti)O₃, (PZT) thin films prepared by rf magnetron sputtering was investigated. The PZT films were deposited at 150, 250 or 340°C and, followed by rapid thermal annealing (RTA). It was found that the crystallographic orientation of the PZT films could be controlled only by the deposition temperature and the ferroelectric properties were dependent upon the orientation of the films. It was suggested that the difference in the atomic mobility at the substrate surface during deposition was closely related to the film orientation. The films with (111) orientation showed relatively high capacitance and the remanant polarization values.