Basma Marzougui
University of Carthage, National Centre of Research in Materials Sciences, Laboratory of Valorization of Useful Materials, Techno Park of Borj Cedria, Soliman, Tunisia
The synthesis of polycrystalline powder is a key step for materials sciences. In this chapter, we present the well-known methods of preparation of powders such as: solid-state reaction, sol–gel, hydrothermal, combustion, co-precipitation. Moreover, synthesis methods by arc furnace, by heating in a “high frequency” induction furnace and by high energy grinding are presented. The obtained powders could be defined by their purity, gain size, crystallinity, and morphology, which are influenced by the synthesis method. In addition, each method is dependent on some parameters like pH, concentration and temperature.
Part of the book: Crystallization and Applications
This chapter is concerned with a study of undoped and doped cuprates of the general formula Ln2CuO4 (Ln = rare-earth metal) and Ln2–xMxCuO4±δ (Ln = rare earth and M = Sr, Ba, Ca, Ln’, Bi, and 3d metal). The crystal structures of the undoped and doped cuprates having the notations (T, T′, T*, S, and O), significantly depend, however, on the synthetic route. The topotactic synthesis is a specific method, which allows the transformation of the cuprate from the T to T′ structure. The importance of these materials originates from the discovery of the unconventional superconductors of the Ce-doped Ln2CuO4. The cuprate materials could function as insulators or semiconductors which are valuable tools in optoelectronic applications. The doped cuprate materials are good ionic conductors and are found useful as electrodes in fuel cell applications. The undoped cuprates reveal high dielectric properties.
Part of the book: Crystal Growth and Chirality