Zian Kighelman

Electromechanical properties and self-polarization in relaxor Pb(Mg1/3Nb2/3)O3 thin films

Pyrochlore free Pb(Mg1/3Nb2/3)O3 (PMN) thin films were prepared from alkoxide-based solution precursors. The influence of different seeding layers and chemical solution on the microstructures is shown. Dielectric, electrostrictive, and piezoelectric properties of the films were characterized in detail. Films show relaxor-like behavior, but with dielectric permittivity which is low (around 4000 at peak) compared to bulk ceramics and single crystals. Several parameters which might be responsible for this lower permittivity are suggested. Electrostrictive coefficients, M and Q, were determined by measuring strain S and polarization P as a function of the electric field (Eac). At large fields (>2.6×106 V/m), S vs P2 appears to deviate from linear behavior possibly suggesting that the electrostrictive coefficient Q becomes nonlinear in this field range. Investigated as-prepared PMN films exhibit piezoelectric response in the absence of a dc electric field (d33=8–20 pm/V). The value of the associated self-polar...

Relaxor behavior and electromechanical properties of Pb(Mg1/3Nb2/3)O3 thin films

Pb(Mg1/3Nb2/3)O-3 (PMN) alkoxide precursor solutions were synthesized and used to prepare thin films by spin coating on TiO2/Pt/TiO2/SiO2/Si substrates. Many parameters like the use of homogeneous and stable precursor solutions and appropriate processing were used to greatly reduce the presence of the nonferroelectric pyrochlore phase. Transmission electron microscopy investigations, dielectric, electrostrictive, and direct current field induced piezoelectric measurements were carried out and have shown that PMN thin films exhibit a relaxor-like behavior

Dielectric and electromechanical properties of ferroelectric-relaxor 0.9 Pb(Mg1/3Nb2/3)O3–0.1PbTiO3 thin films

Pyrochlore free 0.9Pb(Mg1/3Nb2/3)O3–0.1PbTiO3 thin films were prepared from alkoxide-based solution precursors. Preferential (111) crystallographic orientation was obtained on TiO2/Pt/TiO2/SiO2/Si substrates by spin coating. Dielectric, electrostrictive, and piezoelectric properties of the films were characterized in detail. Films show relaxor-like behavior, but with dielectric permittivity which is low (around 4300 at peak and at 340 Hz with Eac=1.6×106 V/m) compared to bulk ceramics and single crystals. Several parameters which might be responsible for this lower permittivity are suggested. The ac and dc field dependences of the dielectric response have been investigated. Electrostrictive coefficients, M11(7.76×10−18 m2/V2) and Q11(1.9×10−2 m4 C−2), were determined by measuring strain and polarization as a function of the electric field (Eac). The maximum field induced piezoelectric d33 coefficient is 100 pm/V and electrostrictive strains up to 1.2×10−3 (with an ac electric field of 140 kV/cm) were meas...

Properties of ferroelectric PbTiO3 thin films

PbTiO3 thin films were prepared from alkoxide solution precursors and crystallized onto Pt/TiO2/SiO2/Si substrates. Microscopy observations revealed that the complexity of the domain walls structure decreased with the grain size. Dielectric, electrostrictive, and piezoelectric properties of the films were characterized in details. A shift of the temperature of the dielectric permittivity maximum due to stresses in the plane of films has been observed. Electrostrictive M and Q coefficients were estimated by measuring strain as a function of the ac electric field amplitude. The d33 vs Edc loops are rectangular with a maximum weak field piezoelectric d33 coefficient equal to 65 pm/V. The dielectric permittivity and piezoelectric nonlinearities can be explained by taking into account domain-walls contributions. Dielectric and piezoelectric aging was investigated. It was found that both coefficients follow logarithmic time dependence, with comparable rates. The aging behavior in the PT films is thus qualitativ...

Relaxor Pb(Mg1/3Nb2/3)O-3 thin films and their electromechanical properties

Pb(Mg1/3Nb2/3)O-3 thin films were prepared from modified alkoxide solution precursors and their dielectric and electromechanical characteristics were investigated. Preparation of the films is very sensitive to processing parameters. The influence of different seeding layers on the microstructures is discussed. Films show relaxer-like behavior, but with dielectric permittivity which is low (4500 at peak) compared to bulk ceramics and single crystals. Large electric de bias fields (up to 120 kV/cm) can be applied to the films. This de field reduces the permittivity, suppresses the frequency dispersion and flattens the permittivity-peak. No anomaly in temperature dependence of the permittivity associated with the held induced transition into, a ferroelectric phase was observed. The maximum field induced piezoelectric d(33) coefficient is around 85 pm/V and electrostrictive strains up to 1.6 10(-3) were measured with an electric field of 30 kV/cm.

Insights in the sol–gel processing of Pb(Mg1/3Nb2/3)O3. The synthesis and crown structure of a new lead magnesium cluster: Pb6Mg12(μ-OAc)6(μ2,η2-OAc)18(μ3,η2-OC2H4OPri)12

The synthesis and molecular structure of a Pb-Mg bimetallic acetatoalkoxide (Pb-6,Mg-12( mu-OAc)(6)(mu(2), eta(2)-OAc)(18)(mu(3), eta(2)-OC2H4OPr1)(12), space group R-3, a = b = 30.032(2), c = 18.855(2) Angstrom, alpha = beta = 90degrees, gamma = 120degrees) are discussed in this article. This compound was isolated as an intermediate during the elaboration of Pb(Mg1/3Nb2/3)O-3 (PMN) using sol-gel process. It results from the reaction of a bimetallic Mg/Nb species with lead acetate in 2-isopropoxyethanol

Stoichiometry and Interdiffusion in PZT Thin Films Studied by Transmission Electron Microscopy

Electrode stability, interdiffusion, phase purity and deviation from stoichiometry at the PZT-electrode interface are key issues in PZT thin film integration. This article highlights the use of transmission electron imaging combined with energy dispersive spectroscopy (EDS) for the investigation of these phenomena. The accuracy of the EDS analysis is discussed. It will be shown that using a standard PZT sample and controlled conditions, reliable analysis can be performed. Diffusion mechanisms have been studied for Pt based electrode systems and RuO2-based electrode systems developed for direct integration onto silicon. The materials studied were composed of stacks of silicon-silicon oxide, an adhesion layer (Ti, Ta or TiOx), an electrode (Pt or RuO2) and PZT (45/55). The PZT was deposited by sol gel using the same parameters to allow for comparison of the different electrodes. Four different electrode / adhesion layer materials were compared (Pt/Ti, Pt/TiOx, Pt/Ta and RuO2 / TiO2). In the case of Pt, lead and oxygen diffusion through the electrode is observed. While the initial Ta layer transforms into a homogeneous pyrochlore phase, the Ti adhesion layer is heavily deformed. In the case of TiOx the lead is mainly incorporated at the interfaces with Pt and with SiO2. No lead diffusion to the adhesion layer is observed for the RuO2 electrode. In-situ sputtering and sol-gel deposition of PZT are also compared. The sol-gel films are close to the right stoichiometry for the perovskite while the sputtered films contained an excess of lead. No sign of second phase is found by X-ray diffraction (XRD), by EDS and by high resolution transmission electron microscopy (HRTEM) which suggests that the excess lead is accommodated in the perovskite lattice.

New Sol-Gel Route for Processing of PMN Thin Films

Pyrochlore free Pb(Mg1/3Nb2/3)O3 (PMN) thin films were prepared from mixed-metal precursors solutions using the sol-gel process. Lead acetate [Pb(CH3COO)2], magnesium acetate [Mg(CH3COO)2] and niobium ethoxide [Nb(C2H5O)5] were used as starting materials, while 2-isopropoxy-ethanol was chosen as solvent. The reactivity of the precursors was investigated in order to understand and control the process and thus to prevent the contamination of the PMN with the pyrochlore phase. The solution was spin-coated on TiO2/Pt/TiO2/SiO2/Si substrate. The thin films were characterized by SEM and XRD while dielectric measurements were performed on the bulk ceramic.

Preparation and electromechanical properties of Pb(Mg1/3Nb2/3)O3 thin film

Abstract Pb(Mg1/3Nb2/3)O3 (PMN) alkoxide precursor solutions were synthesized and used to prepare thin layers on TiO2/Pt/TiO2/SiO2/Si substrates by spin coating. Many parameters like homogeneity of the solution and appropriate processing must be controlled to minimize the pyrochlore formation. Optimization of the processing allowed highly (111)-oriented thin films to be obtained. Dielectric measurements and TEM investigations were performed and showed that PMN thin films exhibit relaxor behavior.

Erratum: “Electromechanical properties and self polarization in relaxor Pb(Mg1/3Nb2/3)O3 thin films” [J. Appl. Phys. 89, 1393 (2001)]

Note: Kighelman, Z Ecole Polytech Fed Lausanne, Swiss Fed Inst Technol, Dept Mat, Ceram Lab, CH-1015 Lausanne, Switzerland Ecole Polytech Fed Lausanne, Swiss Fed Inst Technol, Dept Mat, Ceram Lab, CH-1015 Lausanne, Switzerland422QETimes Cited:0Cited References Count:1 Reference LC-ARTICLE-2001-012View record in Web of Science Record created on 2006-08-21, modified on 2017-05-10