Processing of ferroelectric ceramics and thin films through the microstructure control

Abstract

The subject of this project is the development of ferroelectric ceramics and thin films with controlled microstructure that show electrical properties for aplications such as dielectric, piezoelectric, electrooptics and non volatile memories devices. The ceramic microstructure will be controlled during synthesis through the controlled nucleation of the desired phases, and during the sintering with adequate thermal treatments. The project also seek to controll the microstructure of thin films through the deposition in single crystal substrates with adequate thermal treatment aiming to get epitaxy. It is known that the physical properties of ceramic materials are dependents on its microstructure. Then to obtain reproducible properties are basic conditions that the ceramic microstructure being controlled. Otherwise the microstructure development basically depends on the ceramic powder characteristics (particle size, crystalline phases, agglomeration, surface area, purity, etc) and on the ceramic processing involving forming and sintering. The ferroelectric ceramics and thin films studied in this project are the lead based perovskite such as PZT, PLZT, PMN and PZN, as well as lithium and sodium niobates and the strontium and bismuth tantalate (SBT). Thin films will be prepared through the chemical deposition of organic solution in single crystal substrates using dip-coating, spin-coating and chemical vapor deposition. Dielectric, piezoelectric, electroptics and ferroelectric hysteresis will be determined and related to the ceramic or thin film developed microstructure. It is also objective of this project to develop a new type of modeling to explain the effects of defects and/or dopants in the crystalline structure and its influence on the dielectric, piezoelectric and electrooptics properties. For this purpose ab-initio aiPI, Crystal and Gaussian 94 methods will be used. (AU)