Morphology Control Of Perovskite La_1-xSr_xMnO₃ And The Exploratory Research Of Low Filling Hydrothermal Synthesis

With the modern science and technology galloping in this century,new demands are presented to all subject fields.Micro-nano technology has already spread its foresight to the traditional materials and techniques,of course,this idea will finally point to synthesis area where the materials come from.Chemical synthesis is marching toward “controllable synthesis” and “designed synthesis” after straightforward-outcome era.Nowadays,purity of products and mechanism of synthesis occupy similarly places in the system,as the reason that the knowledge of mechanism and process in one reaction is the beginning of all “controllable” and “designed” synthesis.Perovskite materials have been sought after in various fields since the mid-1950 s.Guided by the new demands mentioned above,we have focused attention on controlling the shape and size of strontium-doped rare earth manganese complex oxides crystalline materials La1-x Srx Mn O3(LSMO)by hydrothermal synthesis.We have prepared four kinds of sizes in cubic crystals(1 ?m?5 ?m?10 ?m and 20 ?m).When it comes to morphological control,several shapes of crystal particles with different exposed area of {111},{110} & {100} crystallographic planes are regulated and controlled,even including the sphaerocrystals which are deemed to contain continuous index facets.All these products provide the most valuable materials not only for application domain but also for crystal facet tailoring mechanism and method.To explore the possible routes in the “black-box” within hydrothermal reaction,we applied the low filling degree to hydrothermal synthesis of strontium-doped rare earth manganese complex oxides La1-x Srx Mn O3(LSMO)and Pr1-x Srx Mn O3(PSMO).The result makes the first successful direct “observation” of processes belonging to hydrothermal synthesis in such a safe and easy way.We have found,in this way,PSMO particles crystallize would draw support from strontium manganite(SMO)as an intermediate crystal product.With this discovery as a credible proof,we explained some problems exiting in previous researches,such as why does the PSMO or LSMO crystallize as the polycrystal with strange form and micron groove.The most valuable significance is that the methodology of low filling degree gives us the feasible probability to light up hydrothermal “black-box” in an easy and safe way.