摘要:

The principle of the operation of the step petalous micromotors based on the effect of the electrostatic rolling on the ferroelectric surface is considered. These micromotors produced by means of microelectronic technology are distinguished as being energy-intensive (more than 1 J/m2at 20–40 V voltage) and they provide precise movement: the step ranges from 10 Å to 100 μm. The technical and experimental data are given characterizing the energetic and mechanical parameters of these micromotors.

ISSN:1058-4587    

DOI:10.1080/10584589908210146

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

We propose that far-infrared reflection and transmission measurements would be a sensitive probe of possible variations in the polarizationPof a ferroelectric near a surface. We present a general formulation based on the Landau-Devonshire model, including both linear and nonlinear processes. Surface effects are described by parametersD, giving the free-energy cost of spatial variations inP, and δ, governing the boundary condition onP. Detailed calculations for linear reflection in normal incidence from a semi-infinite medium are presented. If δ−1= 0 the calculations are analytic and the results for this case serve as a check on the numerical calculations that are applied for general δ. Altogether, the results suggest that the effects ofDand δ should be distinct and measurable.

ISSN:1058-4587    

DOI:10.1080/10584589908210147

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

We consider effects usually ignored in leakage current calculations for thin-film ferroelectrics: The Peltier Effect, The Seebeck Effect, The Thomson Effect, and the pyroelectric effect. The former three are negligible; pyroelectricity is not.

ISSN:1058-4587    

DOI:10.1080/10584589908210148

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The effect of 1 MeV ion implantation on leakage conduction, dielectric and ferroelectric properties of the Pt/Pb(ZrxTi1−x)O3/Pt capacitors is studied for a wide range of implantation doses (1010–1016cm−2). It is shown that the implantation of Pt+, with an implant and vacancy profile peaking at the bottom interface and a dose within the range of 1013–1016cm−2, provokes a strong suppression of the leakage conduction and ferroelectric hysteresis. In addition, ion implantation results in a decrease of the static dielectric constant. Annealing of the specimens at 650°C restores the initial conduction and dielectric properties. The phenomena observed can be interpreted in terms of formation of a non-switching dielectric layer at the interface of the ferroelectric film.

ISSN:1058-4587    

DOI:10.1080/10584589908210149

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The structural and electric properties of PZT thin films deposited by the sol-gel process on RuO2coated stainless steel as well as on bare stainless steel were studied and compared. As-deposited amorphous RuO2thin films on stainless steel were transformed to pure rutile-type RuO2at temperatures ranging from 400°C to 600°C, the resistivity of which had a value less than 200 μΩ ° cm. The PZT films processed on RuO2needed slightly higher temperature (610°C) in order to be completely transformed into the perovskite phase than PZT on stainless steel (600°C). The films showed best ferroelectric properties when depositing it on the 100 nm thick RuO2bottom electrodes fired at 400°C for 10 minutes. The hysteresis loops of the PZT films were more slim when being processed on RuO2coated stainless steel than on bare stainless steel. For the RuO2bottom electrodes the values of coercive field decreased to about 55% of those without a RuO2layer.

ISSN:1058-4587    

DOI:10.1080/10584589908210150

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

In the sol-gel processing of the ferroelectric thin films of PbZrxTi1-xO3(PZT), solution precursor characteristics have been long considered as a factor, which affects thin film microstructure and orientation. In this study, we used a hybrid solvent of acetic acid and methanol to prepare PZT precursor sols. The structures of PZT precursor sols before and after hydrolysis were characterised by using NMR (nuclear magnetic resonance), PCS (photon correlation spectroscopy), and SAXS (small angle X-ray scattering) techniques. We also measured the rheological properties of the PZT precursor solutions. The measurements revealed that methoxy ligands, which were bonding to metals, were completely replaced by acetate ligands in the unhydrolysed sols. The particles in our PZT sols are chain-like and their average size increases linearly on a logarithmic scale after extra water was added due to the hydrolysis and condensation reactions. To examine the relationship between the film crystallisation and the particle size in the precursor sols, the films were fabricated with different particle sizes and then annealed at 480°C. The crystallisation of the thin films was investigated using X-ray diffraction. Under the identical fabrication conditions, pyrochlore phase appeared in the films prepared with the solutions of larger particle sizes. Ferroelectric properties were degraded when using the solutions with large particles.

ISSN:1058-4587    

DOI:10.1080/10584589908210151

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

By means of r.f. sputtering the polycrystalline Pb(Zr0.53Ti0.45W0.01Cd0.01)O3ferroelectric thin films ofdf= (0.5 − 10) μm in thickness have been obtained. A disk ceramics obtained by hot pressing method or a layer of powdered ceramic samples was used as a target. On the basis of structure analysis by X-ray diffraction conditions which are necessary for obtaining thin ferroelectric, stoichiometric films having a perovskite-type structure have been determined. Regions of amorphous film deposition, pyrochlore-type structure or mixture of pyrochlore-type and perovskite-type structure are also presented in diagram “working gas pressureversussubstrate temperature” (p02-Ts). New experimental data on pyrochlore-type structure metastability and its conversion into perovskite-type structure caused by thermal treatment are obtained.

ISSN:1058-4587    

DOI:10.1080/10584589908210152

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor