Hydrothermal Synthesis And Characterization Of The B-Site Doped Manganites

New materials play an a leading role in human social progress and development of high technology, is significant to improve the country's comprehensive national strength and national defense strength, is the key to the development of modern industry. Material is an expansionary area. With the rapid development of high-tech, much more materials'performance and quality was required. It plays an important part in developing high technology, upgrading traditional industries, and enhancing comprehensive national defense strength. The world's developed countries have attached to the research of new materials. Perovskite-type manganites are a class of new functional materials with unique electrical, magnetic, catalytic properties. It has been caused more concern since the giant magneto-resistance(GMR) was founded in some doped manganites.High-temperature solid-state reaction method is the most conventional method to the manganites synthesis . But the high temperature may lead high cost and more impurities, so more mild synthesis technology has been used , hydrothermal synthesis is one of which .The appearance of Mn4 + ions arose double exchange interaction Mn3+-O-Mn4+ in the system. Hydrothermal Synthesis of A-bit alkaline earth ion doped manganese oxides have been widely studied. This approach has the advantages which other synthetic technology can't replace of, most new compounds and materials can be prepared. And it has specificity in physical and chemical properties. Therefore it has shown a broad development prospects. The method often used in the synthesis of metastable phase compounds due to its low temperature. The introduction of holes in singlet state formed conduction band. So many interesting physical phenomena was founded in manganites, such as ferromagnetism in room temperature, atomic level of P-N junction, metal - insulator phase transition and so on. The report for the B-site doped manganites still limited to the solid-phase method. It is few about hydrothermal method report.In view of this, a series of B-site doped manganites synthesized through mild hydrothermal method. We fumbled the suitable synthetic condition (mole rate/ alkalinity/time/temperature).And explored products'composition, structure, morphology, magnetic properties, and thermal stability preliminarily.1. A series of purity, high crystalline A-site Sr-doped with and B-site Fe-doped manganese oxides La1-x-ySrxKyFe0.5Mn0.5O3(x=0.1-0.4)was synthesized by hydrothermal synthesis, with controllability modulation of the A-site composition. Optimal conditions for reaction series of samples has been detailed studied. And all samples were characterized and carried through a series of discussions of the property. Regularity results were founded in our samples.2. A series of earth Ni-doped RMn1-xNixO3 was reared by mild hydrothermal treatment. Four kinds of rare earth Y, Gd, Tb, Ho was chose elements for research. And all samples were characterized and carried through a series of discussions of the property. The different rare earth elements had diverse purity and morphology.