【摘要】 采用固相反应法制备了一系Ｌａ_１－ｘＮａ_ｘＭｎＯ_３多晶样品。研究了样品的微结构、磁电阻、磁化强度以及居里温度等性质。发现随着Ａ位平均离子半径＜ｒ_Ａ＞的减小，样品的居里温度下降，磁电阻增大。另外，实验还发现了磁电阻与磁化强度之间有着密切的联系。更多还原

【Abstract】 A series of polycrystalline samples of La_1-xNa_xMnO₃ was prepared through solid states reactions processing in air. The microstructure,magnetoresistance, magnetization and Curie temperature of the samples have been studied. With decreasing the average ionic radius of La site <r_A>, we found a decrease in To and an increase in the magnitude of magnetoresistance. In addition, the experiment demonstrates the close relationship between the magnetoresistance and the magnetization.更多还原