| This paper mainly addressed the influence of different coprecipitation technology on the preparations and properties of La0.7 (Ca0.53Sr0.47)0.3MnO3 (LCSMO) polycrystals.We adopted chemical coprecipitation method to prepare LCSMO polycrystals, comparing the influence of precipitators between oxalate and salvolatile, dispersant about different contents of oleic acid and PVA, the different temperature of coprecipitation. Powder prepared by coprecititation method was investigated by means of pulverous granularity measurement and DTG/TA curve measurement. LCSMO polycrystals were surveyed by R-T curve measurement, X-ray diffraction measurement, caculations of relative density and parametersThe result of DTG/TA measurement indicates that the materials prepared by salvolatile coprecipitation method can be sintered at lower temperature (300k) and with shorter time than those obtained with solid state reactions for preparations LCSMO. The results of pulverous granularity measurements show that the homogeneousness and size distribution of samples prepared by salvolatile are superior to those prepared by oxalic acid.The R-T curve of La0.7 (Ca0.53Sr0.47)0.3MnO3 prepared by utilizating oleic acid as dispersant is superior to those PVA. LCSMO prepared by optimal value of oleic acid demonstrate large TCR, high Tp. A sensitive room-temperature Bolometer device can be made firstly by using CMR polycrystals.Besides, semiconductor to metal transition temperature Tp of LCSMO was influenced by temperature of coprecipitation .Experiment certifies that the optimal value of temperature is about 75 ℃.La0.7 (Ca0.53Sr0.47)0.3MnO3 films prepared on LaAlO3 substrate which has 10° of obliquity using polycrystals prepared by salvolatile coprecipitation method according to PLD method. The phenomenon of Laser Induced Thermoelectric Voltage ( L1TV) was observed from the LCSMO films and the responsive signals is quicker than LaCaMnO3 films. Therefore, LCSMO films can be prepared to rapid responsiveness detectors. |
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