在温和条件下巨磁阻材料La_(0.5)Ba_(0.5)MnO_3的水热合成与表征

Hydrothermal Synthesis of a Giant Magnetoresistance Material La 0.5 Ba 0.5 MnO 3 Under Mild Conditions

报道了在温和条件下巨磁阻材料Ｌａ０．５Ｂａ０．５ＭｎＯ３的水热合成．系统地研究了原料配比、碱度、时间和温度对产物合成的影响，在最佳合成条件下得到了结晶度较高的纯相，并通过ＸＲＤ、ＤＴＡ－ＴＧ、化学分析及碘量法对产物进行了表征．该化合物属立方晶系，晶胞参数为ａ＝０．３９１３ｎｍ，Ｖ＝０．０５９９０ｎｍ３，Ｍｎ的平均价态为３．５，在１Ｔ的外磁场下，磁阻比（ＭＲ）的极大值为２９％．

A giant magnetoresistance material La 0.5 Ba 0.5 MnO 3 was prepared by hydrothermal method at 240 ℃ for 24 hours. The product was characterized by X ray powder diffraction, differential thermal analysis thermogravimetric analysis, chemical analysis, and iodometry. The compound crystallizes in a cubic system with cell parameters a =0.391 3 nm and V =0.059 90 nm 3 . The average valence state of manganese was 3.5, and the magnetoresistance (MR) is about 29% at 1 T.