庞磁电阻材料Sr₂FeMoO₆的性能及其穆斯堡尔谱研究

庞磁电阻材料Sr 2 FeMoO 6 的性能及其穆斯堡尔谱研究 Investigations of Properties And Mossbauer Spectrums of Ordered Doubleperovskite Sr 2 FeMoO 6 沈祖炎 SHEN Zuyan 1 first-author 徐斌富 XU Binfu 1 戴明星 DAI Mingxing 1 武汉大学物理科学与技术学院,湖北,武汉,430072 武汉大学物理科学与技术学院,湖北,武汉,430072 School of Physics and Technology, Wuhan University School of Physics and Technology, Wuhan University 应用传统的陶瓷制备方法 ,制备了烧结温度分别为 12 0 0℃和 12 5 0℃的双钙钛矿结构庞磁电阻（GMR）材料Sr2 FeMoO6样品 通过X射线衍射、室温磁阻和穆斯堡尔谱研究 ,发现较低温度烧结的样品晶粒相对较小而磁阻较大 ,从而暗示晶界上的自旋极化电子对磁电阻效应有明显贡献 同时 ,通过观察不同温度下的穆斯堡尔谱 ,看到了晶界上Fe离子磁状态的改变 ,这从另一角度证实晶界上的载流子散射是室温下电阻产生的主要原因 ,而晶粒之间自旋极化电子的跳动受到外加磁场的影响 ,产生了磁电阻效应 The ordered doubleperovskite Sr 2 FeMoO 6 polycrystalline samples were sintered in different temperatures of 1 200 ℃ and 1 250 ℃.By studying the result of XRD and roomtemperature magnetoresistance, we found that the sample sintered on 1 200 ℃ have greater grain size and less magnetoresistance than that of 1 250 ℃.It imply that the intergrain spinpolarized electrons were responded for the roomtemperature magnetoresistance. Through the mossbauer spectrums, we can observe directly the changing of the ions Fe in grain boundaries. It confirm that the spindependent scattering in grain boundaries is the most often reason of the roomtemperature resistance and the dynamics of the spinpolarized electrons intergrain were effected by the out megnetism field in another way. 双钙钛矿 磁电阻 穆斯堡尔谱 自旋极化载流子 doubleperovskite magnetoresistance mossbauer spectrums spinpolarized O481.4;TM284 国家自然科学基金!资助项目 （59972 0 2 4 ） 2001-01-01 2021-04-01 1