| Manganite compounds of general formula, A1-xBxMnO3(A is a rare-earth element, B is an alkaline earth metal) are of high technological importance because of their interesting electronic and magnetic properties. More recently, the perovskite manganite compounds, A1-xBxMnO3 have received much attention because of their gigantic magnetoresistance (GMR) and charge ordering properties. GMR property of these materials finds potential applications in the field of magnetic sensors, in memory applications and in prototype disc drives employing read-head technology. In manganite perovskites, substitution of divalent ions (alkaline earth metals viz. Ca, Sr, Ba) in the A sublattice, introduces Mn4+ ions or holes into the system. It is generally considered that the concentration of holes is equal to the concentration of divalent cations because of the charge compensation by controlled valencies.A number of publications exist in the literature on the synthesis of manganite perovskites. Recently, Stephanie et al. published a review on porous manganese oxide materials. It discussed the various known techniques for the preparation of MnO2 and other manganese oxide materials. Here, we report a novel self-propagation high temperature synthesis (SHS) method for the preparation of manganite perovskites, involving a redox reaction. This method helps to retain higher-oxidation states Mn ions in the system. Thereby, modifying the electronic and magnetic properties. Various perovskite compositions have been prepared through this method and their structure, electronic and magnetic properties have been studied.In this paper, La2O3, SrO2i Mn, NaClO4, KMnO4 were used as raw materials and were synthesized into La1-xSrxMn03 powder by employing self-propagating high-temperature synthesis (SHS) technology and filtration processing. In addition, the mechanism of chemical reaction and microstructure formation process of La2O3-SrO2-Mn-NaClO4-KMnO4 system was studied. Furthermore, La1-xSrxMnO3 powder was sintered with hot-pressing method and spark plasma sintering. The electronic and magnetic properties of samples were tested. At last,the relationship between microstructure and properties for La1-xSrxMnO3 powder was analyzed.La1-xSrxMnO3 powder was produced by SHS technology. During the SHS process, different techniques through the synthesis were discussed and studied. By control the adulteration of KMnO4 powder in the raw materials, we found the adulteration of KMn04 powder decrease the dosage of easy melted metal Mn, and release the hot-trap problem, enhance the diffusion velocity as well as cut down the synthesis temperature and combustion propagation velocity of the system. The in situ prepared MnO2 made for the production of La1-xSrxMnO3 phase, and avoided the semi-finished phase. The influence of raw materials density to the SHS process was also reviewed. The hole volume ratio also influenced the combustion temperature and diffusion velocity.The results of analysis of different thermal analysis (TG-DTA) and X-ray diffraction (XRD) showed following thermodynamics processing of La2O3-SrO2-Mn-NaClO4-KMnO4 system. The absorptive water of raw mixtures was dehydrated at about 150℃, and KMnO4 was melted and decomposed at 280 ℃. The vehement exothermal reactions were happened between Mn-SrO2, Mn-NaClO4, and Mn-KMnO4 systems at about 370℃~570℃, in this process, SrO2 also reacted with the CO2 in the air. Metal Mn was melted and transferred into liquid phase at high temperature. At 800℃ The product NaCl melted and vaporized. The reactions of La2O3-SrO2-Mn-NaClO4-KMnO4 system were nearly ended. But at some point example 950℃, 1050℃, some phase transformed.Results of microstructure formation by SEM and CFQ methods showed that SrO2, NaClO4, KMnO4 were reduced and wrappaged by liquid Mn.The leached product was sintered by hot pressing method and spark plasma sintering. The densification mechanism of La1-xSrxMnO3 powder during the sintering process was studied. It was found that initial well-proportioned raw materials became asy...
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