【摘要】 采用溶胶-凝胶法成功制备了双层钙钛矿锰氧化物Pr(Sr0.2Ca0.8)2Mn2O7纳米颗粒样品,并研究了样品的相结构和显微形貌及样品的磁性.X射线衍射分析结果表明样品中没有出现明显的杂相,SEM分析晶粒平均尺寸约为35nm,EDS测得的样品原子百分比表明成分基本没有偏析,Scherrer公式计算晶粒平均尺寸与SEM测试结果相同约为35nm.在场冷(field cooling FC)和零场冷(zero field cooling ZFC)模式测得的磁化强度-温度(M~T)曲线上,没有观察到300K时电荷有序转变;通过不同温度下磁化强度-磁场强度(M~T)曲线可以清楚的看出,Pr(Sr0.2Ca0.8)2Mn2O7纳米样品在5K和77K时都表现出铁磁行为,表明样品中铁磁(ferromagnetic FM)团簇磁矩已经开始有序排列形成铁磁态.更多还原

【Abstract】 Double layered perovskite manganites Pr(Sr0.2Ca0.8)2Mn2O7polycrystalline samples were prepared by sol-gel method,and its phase compositions,micro structures and magnetic properties were studied.Experiment results show that impurity phase is not found in the sample by means of X-ray diffraction and the average grain size of the sample is about 35 nm.The sample was studied by means of Scherrer formula and SEM.Magnetic measurements result show that charge ordering transition is not observed in the curves of temperature dependence of the magnetization in ZFC(zero field cooling ZFC)and FC(field cooling FC)modes.FM(ferromagnetic FM)state formation is proved by the hysteresis loop at T=5Kand T =77K.更多还原