Search

Your search keyword '"Vilarinho, Paula Maria"' showing total 88 results
Start Over Author "Vilarinho, Paula Maria"
88 results on '"Vilarinho, Paula Maria"'

12. Terbiumpolyoxotungstate Anions as Building Units to Fabricate Nanostructured Films

Author

Sousa, Filipa Lourosa, Soares-Santos, PCR, Nogueira, HIS, Ferreira, RAS, Cavaleiro, AMV, Carlos, LD, Trindade, T, and Vilarinho, Paula Maria

Subjects
Nanostructure, Photoluminescence, Materials science, Hydrochloride, Mechanical Engineering, chemistry.chemical_element, Nanotechnology, Terbium, terbiumpolyoxotungstates, Condensed Matter Physics, Polyelectrolyte, Allylamine, chemistry.chemical_compound, thin films, chemistry, Mechanics of Materials, nanostructures, Polyoxometalate, polyoxometalates, photoluminescence, General Materials Science, Thin film
Abstract

A layer-by-layer assembly method was employed to fabricate multilayered films containing the terbium heteropolyanions K6[Tb(BW11O39)(H2O)3]·32H2O and Ky[Tb(XW11O39)2]·nH2O (X = Si and P) and the polyelectrolytes poly(4-styrenesulfonate) and poly(allylamine hydrochloride). A comparative study on the optical properties of the films containing distinct polyoxometalates and different types of multilayers was carried out. The photoluminescence of the solid polyoxometalates and of the resulting films was investigated.

Published
2006
Full Text
View/download PDF

15. Mechanical strain engineering of dielectric tunability in polycrystalline SrTiO3 thin films.

Author

Tkach, Alexander, Okhay, Olena, Reaney, Ian M., and Vilarinho, Paula Maria

Abstract

Optimizing performance using low cost scalable processing and substrates is critical if functional oxide thin films are to achieve commercialisation. Here, we present a comprehensive investigation of the role of low cost Al2O3, SrTiO3, and MgO substrates in the structure, microstructure and electrical properties of SrTiO3 (ST) thin films, deposited by sol–gel processing. We demonstrate that the dielectric properties of polycrystalline ST films depend on the strain/stress induced by the substrates. ST films deposited on Al2O3/Pt substrates under a high tensile stress possess the smallest grain size and present the lowest value of the relative permittivity, εr, with the lowest dielectric tunability. In contrast, ST films deposited on MgO/Pt substrates, under the highest compressive stress, have the highest value of εr, tunability and polarization. It is thus demonstrated that for polycrystalline ST films the relative permittivity and dielectric tunability may be optimised through an induced compressive stress state. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

17. NATO Advanced Study Institute on Scanning Probe Microscopy : Characterization, Nanofabrication and Device Application of Functional Materials

Author

Vilarinho, Paula Maria, Rosenwaks, Yossi, and Kingon, Angus

Subjects
Engineering
Abstract

As the characteristic dimensions of electronic devices continue to shrink, the ability to characterize their electronic properties at the nanometer scale has come to be of outstanding importance. In this sense, Scanning Probe Microscopy (SPM) is becoming an indispensable tool, playing a key role in nanoscience and nanotechnology. SPM is opening new opportunities to measure semiconductor electronic properties with unprecedented spatial resolution. SPM is being successfully applied for nanoscale characterization of ferroelectric thin films. In the area of functional molecular materials it is being used as a probe to contact molecular structures in order to characterize their electrical properties, as a manipulator to assemble nanoparticles and nanotubes into simple devices, and as a tool to pattern molecular nanostructures. This book provides in-depth information on new and emerging applications of SPM to the field of materials science, namely in the areas of characterisation, device application and nanofabrication of functional materials. Starting with the general properties of functional materials the authors present an updated overview of the fundamentals of Scanning Probe Techniques and the application of SPM techniques to the characterization of specified functional materials such as piezoelectric and ferroelectric and to the fabrication of some nano electronic devices. Its uniqueness is in the combination of the fundamental nanoscale research with the progress in fabrication of realistic nanodevices. By bringing together the contribution of leading researchers from the materials science and SPM communities, relevant information is conveyed that allows researchers to learn more about the actual developments in SPM applied to functional materials. This book will contribute to the continuous education and development in the field of nanotechnology.

Published
2005

22. Defects and charge transport in Mn-doped K0.5Na0.5NbO3 ceramics.

Author

Rafiq, Muhammad Asif, Tkach, Alexander, Costa, Maria Elisabete, and Vilarinho, Paula Maria

Abstract

The relationship between charge transport, defects and ferroelectric response is established for K0.5Na0.5NbO3 (KNN) and Mn-doped KNN ceramics. At room temperature the conduction in KNN is associated with hole transport and can be suppressed by Mn doping. Because of that a less leaky ferroelectric hysteresis loop is obtained for Mn-doped KNN. At high temperatures the conduction is dominated by the motion of ionized oxygen vacancies, the concentration of which increases with Mn doping. This work adds relevant information on KNN and leverages its potential application. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
View/download PDF

47. Functions of NC-AFM on Atomic Scale

Author

Morita, S., Oyabu, N., Nishimoto, T., Nishi, R., Custance, O., Yi, I., Sugawara, Y., Vilarinho, Paula Maria, editor, Rosenwaks, Yossi, editor, and Kingon, Angus, editor

Published
2005
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results