摘要
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 。
The ordered doubleperovskite Sr_2FeMoO_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.
出处
《武汉大学学报（自然科学版）》
CSCD
北大核心
2001年第1期103-105,共3页
Journal of Wuhan University(Natural Science Edition)
基金
国家自然科学基金!资助项目 (59972 0 2 4 )
