Hydrothermal Synthesis And Characterization Of The Doped Titanates And Manganites

The ABO3titanate and RMn2Os multiferroic materials are inorganic functional materials adjusting to development of communication and information storage technology. There are mang deficiencies in using frocess, so people have done a lot of work to improve functional materials.In these methods, doping different element in parent compounds is a effective one.The classics method of the synthesis of oxide compounds is high-temperature and solid-phase method, although this method is simple, but its shortcoming cannot be ignored, for example, high-temperature is needed in sintering process, and there will be miscellaneous in products. It causes difficulties for further physical and chemical tests.In the thesis,our goals are to dope different element in parent compounds with the hydrothermal method. A site doped with K,Na perovskite type titanate and B site doped with Fe RMn2O5type manganate are all synthesized successfully. We focus on the synthetic reaction,method composition of products. At last,we study the information of dielectric properties and magnetic properties to see changes of properties after doped products.1. Series compounds with B site doped DyMn2O5have been synthesized under low-temperature hydrothermal conditions, reactant ratio determined composition of products. We achieve the controllability of composition. Study results indicate a series samples of DyMn2-xFexO5(x=0.1-0.5) all belong to orthorhombic structure and pbam point group.We also discusse effect of Fe doping into parent compound,find that compounds remain antiferromagnetism,but Neel Temperature increasing from45K to55K.2. New Chemicals La0.65K0.18TiO3and Na0.5TiO3have been synthetized with hydrothermal melthod. We focus on the synthetic reaction,method composition of products. La0.6sK0.18TiO3belong to tetraonal system and Laos Na0.5TiO3belong to cubic system.The information of dielectric constant indicates these dielectric materials belong to highpermittivity ceramic.The information of XRD, SEM indicate that products have high purity and crytallinity. Controllability of composition displays characteristics of stability of hydrothemal melthod.