钙钛矿La_(0.75)Na_(0.25)MnO_3外延膜的制备及磁电特性研究  

Preparation as well as magnetic and electrical properties of La_(0.75)Na_(0.25)MnO_3 epitaxial film

作　　者：朱金山[1] 韩立安[1] 

机构地区：[1]西安科技大学理学院,陕西西安710054

出　　处：《宝鸡文理学院学报（自然科学版）》2010年第2期21-23,46,共4页Journal of Baoji University of Arts and Sciences(Natural Science Edition)

基　　金：陕西省自然科学基金资助(ZK2007F46)

摘　　要：目的研究单价碱金属Na替代对钙钛矿La MnO3结构及磁电特性的影响。方法通过射频磁控溅射在单晶LaAlO3(100)衬底上生长了膜厚为120 nm的La0.75Na0.25MnO3外延膜,用X射线衍射仪、原子力和超导量子干涉仪、直流四探针法对其进行了表征。结果结果表明,薄膜为赝立方钙钛矿结构,具有良好的单晶外延结构和岛状生长模式。居里温度TC=270 K,在居里温度附近,发生铁磁-顺磁转变。此材料呈现出一种典型的自旋玻璃特性,是由于应力造成的。在1 T磁场下,磁电阻极大值为40.3%。结论 LaNaMnO外延膜的制备为CMR薄膜的低场和室温条件下的广泛应用提供了潜在的价值。Aim In order to investigate the influence of univalent alkaline metal Na doping on the structure as well as magnetic and electrical properties of perovskite LaMnO3. Methods Using RF magnetron sputtering method, La0.75 Na0.25 MnO3 thin films have been epitaxially grown on （100） LaAlO3 single-crystal substrates. The thin film was characterized with the method of X ray diffraction, atomic force micrograph, superconducting quantum interference device and d. c. four-probe. Results The result shows that the film has a good epitaxial direction （100） and island growth-mode. The Curie temperature is 270 K. Near the Curie temperature, the magnetic property shows a transition from ferromagnetism to paramagnetism. La0.75 Na0.25 MnO3 thin film exhibits a characteristic of spin glass state, which is due to strain effects. The thin film has quite a distinctive magnetoresistance effect which is 40.3% near the Curie temperature when the magnetic field is 1 T. Conclusion The striking results suggest that the preparation of La0.75Na0.25 MnO3 epitaxial film provides potential value for the extensive use of CMR film on the condition of low magnetic field and room temperature.

关 键 词：La0.75Na0.25MnO3外延膜 磁性 磁电阻 

分 类 号：O482.5[理学—固体物理]