995 resultados para 47-398D


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Fatigue is an important problem to be considered if a ferroelectric film is used for non-volatile memory devices. In this phenomena, the remanent polarization and coercive field properties degrades in cycles which increase in hysteresis loops. The reasons have been attributed to different mechanisms such as a large voltage applied on ferroelectric film in every reading process in Ferroelectric Random Access Memory (FeRAM) or memories for digital storage in computer, grain size effects and others. The aim of this work is to investigate the influence of the crystallization kinetics on dielectric and ferroelectric properties of the Pb(Zr0.53Ti0.47)O-3 thin films prepared by an alternative chemical method. Films were crystallized in air on Pt/Ti/SiO2/Si substrates at 700 degrees C for 1 hour, in conventional thermal annealing (CTA), and at 700 degrees C for 1 min and 700 degrees C 5 min, using a rapid thermal annealing (RTA) process. Final films were crack free and presented an average of 750 nm in thickness. Dielectric properties were studied in the frequency range of 100 Hz - 1 MHz. All films showed a dielectric dispersion at low frequency. Ferroelectric properties were measured from hysteresis loops at 10 kHz. The obtained remanent polarization (P-r) and coercive field (E-c) were 3.7 mu C/cm(2) and 71.9 kV/cm respectively for film crystallized by CTA while in films crystallized by RTA these parameters were essentially the same. In the fatigue process, the P, value decreased to 14% from the initial value after 1.3 x 10(9) switching cycles, for film by CTA, while for film crystallized by RTA for 5 min, P, decreased to 47% from initial value after 1.7 x 10(9) switching cycles.

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ECLAC Forecasts 5% Growth in 2006 for Latin America and the Caribbean Changing Role of the Family in Social Protection Op-ed by ECLAC's Executive Secretary, José Luis Machinea. Latin America and the High-Level Dialogue on International Migration and Development Highlights. On the Difference between Resources Generated within the Region and the Resources Available to its Residents Indicators Science, Innovation and Competitiveness: Experiences from Australia and New Zealand Recent titles Calendar of events

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* América Latina y el Caribecrecerá en torno al 5% en 2006 * El papel de la familia en laprotección social * Opinión de José Luis Machinea: América Latina y el Caribefrente al Diálogo de altonivel sobre migracióninternacional y desarrollo *Precisiones: Acerca de las diferencias entrelos recursos que se generan enla región y los que estándisponibles para sus habitantes *Indicadores* Ciencia, innovación ycompetitividad: experienciasde Australia y Nueva Zelandia * Publicaciones recientes* Calendario

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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