巨磁电阻材料(La_(1-x)Gd_x)_(2/3)Ca_(1/3)MnO_3的制备工艺及其结构研究  

Study on Preparation and Structure of Gigantic Magnetoresistivity Materials (La_(1-x)Gd_x)_(2/3)Ca_(1/3)MnO_3 Compounds

作　　者：罗广圣[1] 刘光华[1] 周正有[1] 甘建萍[1] 欧阳小吕[1] 

机构地区：[1]南昌大学材料科学与工程学院,南昌330031

出　　处：《航空材料学报》2008年第1期13-17,共5页Journal of Aeronautical Materials

基　　金：江西省教育厅科技项目(赣教技字2006-25);南京大学固体微结构国家重点实验室基金项目(M041916)

摘　　要：采用固相反应法制备巨磁电阻材料（La1-xGdx）2/3Ca1/3MnO3和La1-xZnxMnO3。La2/3Ca1/3MnO3样品在1200～1400℃等五个不同温度下烧结12h;（La1-xGdx）2/3Ca1/3MnO3（x=0.2,0.4,0.6,0.8,1.0）样品系列在1350℃下分别烧结12h和24h,另外样品La1-xZnxMnO3（x=0.1,0.5,0.9）系列在1350℃下烧结24h。利用X射线衍射（XRD）和扫描电镜（SEM）对各样品晶体结构和表面微观结构进行了研究。X射线衍射结果表明,所有样品晶体结构基本不变,保持钙钛矿结构（空间群为Pnm a）,但随着掺杂量的增加,样品（La1-xGdx）2/3Ca1/3MnO3和La1-xZnxMnO3系列的晶格常数和晶胞体积发生了变化,并且产生了杂质相,导致对结构很敏感的这些材料的磁电性能发生变化。扫描电镜结果表明,样品La2/3Ca1/3MnO3在1400℃时烧结效果最好。The samples of （La1-xGdx）2/3Ca1/3 MnO3 and La1-xZnxMnO3 were prepared by solid-state reaction method. Five samples of La2/3 Ca1/3MnO3compounds were sintered at the temperature range from 1200℃ to 1400℃ for 12 hours respectively, and two same groups of samples （ La1-xGdx ） 2/3Ca1/3MnO3 （x = 0.2,0.4,0.6,0.8,1.0） compounds were sintered at the temperature 1350℃ for 12 and 24 hours respectively, and samples La1-x Zn M nO3 （x = O. 1,0.5,0.9） compounds were sintered at the temperature 1350℃ for 24 hours. The structure and the surface micro-structure of these samples were studied by the X-ray diffraction patterns and the SEM photograph, respectively. It is showed by X-ray diffraction patterns that all samples structure keep same perovskite structure with space group Pnma, but that the lattice parameters and the cell volume of the samples （La1-x Gdx）2/3 Ca1/3 MnO3 and La1-x Znx MnO3 compounds change and the impure phase appear with the doped contents increasing. The magnetoresistance materials are sensitive to the structure, and hence the magnetoelectric properties change. From the SEM photograph it is exhibited that the surface structure of the samples of La2/3Ca1/3MnO3compound sintered at the temperature 1400℃ is the perfect.

关 键 词：巨磁电阻 晶体结构 表面结构 制备工艺 

分 类 号：TG146.2[一般工业技术—材料科学与工程]