【摘要】 研究了纳米晶类钙钛矿型锰氧化物La0.7Sr0.3Mn0.95Fe0.05O3和La0.7Ca0.3MnO3在不同压力、高温处理后的导电性质.结果表明,在室温高压成型样品具有很高的电阻率,居里温度TC附近磁电阻效应很小;随处理压力的增加,电阻率先是降低,至11GPa时达最低点,之后升高.高温处理过的样品经一定压力处理后,其电阻随温度变化曲线的金属绝缘体转变峰向低温跃变,并伴随电阻率的大幅增加.更多还原

【Abstract】 The conductivity and magnetic properties of La 0.7 Sr 0.3 Mn 0.95 Fe 0.05 O 3 and La 0.7 Ca 0.3 MnO 3 nanocrystalline system prepared by high pressure and sintering method were investigated. The samples pressed under high-pressure at room temperature showed a huge resistivity and a small magnetoresistivity effect at the Curie temperature ( T C). With the increase of high pressure, the resistivity decreases, at \%P\%=1\^1GPa reaches a minimum, and then increases. After processing the samples by high pressure, which were first sintered at high temperature, the resistivty increases, and metal\|insulator transition shifts towards lower temperature.更多还原