Study On Preparations And Properities Of La_1-xSr_xMnO₃ With Perovskite Structure

Perovskite oxide materials have attracted great interest for their excellent electromagnetic properties and colossal magnetoresistance effect and wide potential applications in the field of information technique. Many works focus on the doped rare-earth manganate, However, there are still many problems to be solved, For example, the preparation of such materials is still very difficult and seriously restricting the further study and application of materials. Therefore, we will use different methods to prepare perovskite La1-xSrxMnO3 materials in this paper and study the influences of the Sr-doping level on the crystal structures and electromagnetic properties. The main contents are presented as follows:In chapter 1, the research history of the manganites is briefly introduced:the crystal structure and lattice distortion, the electronic and magnetic Phase diagrams of La1-xSrxMnO3 and other systems, the essential physical mechanism such as the double exchange interaction, the Jahn-Teller effect and the super exchange interaction, the charge ordering and other related physical properties.In chapter 2, polycrystalline La1-xSrxMnO3 films of different Sr-doping level were successfully prepared on crystalline silicon substrates by polymer-assisted deposition at a relative low temperature (950℃). The influences of the Sr-doping level and SrMnO3 buffer layer on the microstructure of La1-xSrxMnO3/Si films were systematically studied. Results showed that the crystal structures of La1-xSrxMnO3 films changed from orthorhombic to rhombohedral in the doping range of 0