Nd-Sr-Mn-O钙态矿锰氧化物的低场磁电阻效应  

Low Field Magnetoresistance Effect in Nd-Sr-Mn-O Perovskite Manganites

作　　者：崔旭高[1] 夏洪旭[1] 张世远[1] 杨名[2] 康琳[2] 杨森祖[2] 

机构地区：[1]南京大学固体微结构国家重点实验室物理系,江苏南京210093 [2]南京大学电子科学与工程系,江苏南京210093

出　　处：《中国稀土学报》2003年第1期31-35,共5页Journal of the Chinese Society of Rare Earths

基　　金：国家973项目(G1999064508);国家自然科学基金资助项目[19890310(4)]

摘　　要：采用固相烧结法和脉冲激光沉积法分别制备了钙态矿型锰氧化物Nd1-xSrxMnO3(x=0.1,0.2,0.3,0.4,0.5)大块多晶和Nd0.7Sr0.3MnO3在(100)LaAlO3基片上的单取向薄膜样品,分别研究了这些样品的磁电阻效应。研究表明,在多晶样品中,x=0.3时具有最大的磁电阻比,其值在240K和1T磁场下可达24.2%。对于同一成分的外延薄膜,发现磁电阻随着沉积时基片温度Ts的升高而下降,当Ts=500℃时的制备态薄膜在同样条件下的磁电阻可达84%,随着外加磁场增大到5T,磁电阻将线性增大到275%。并讨论了造成单取向膜和块材磁电阻不同的原因。The polycrystalline samples of Nd1xSrxMnO3 with x ranging from 0.1 to 0.5 and epitxial thin film of Nd0.7Sr0.3MnO3 were prepared by conversational solidstate reaction in air, and pulse laserdeposition (PLD) method, respectively. The colossal magnetoresistance effect of these samples was studied. The results indicate that in this series of polycrystalline samples, a maximum MR of ～24.2% is obtained under a magnetic field of 1 T at the temperature of 240 K for x=0.3. For epitaxial thin films with the same composition, it is found that their MR measured under the same condition has a maximum up to 84% at the deposition temperature of Ts =500 ℃ and decreases with increasing Ts. With increasing the applied field to 5 T, the MR of the film increases to 275% linearly at the temperature of 240 K. Finally, the possible reason causing the difference in MR between bulk materials and thin films was discussed.

关 键 词：凝聚态物理 磁电阻效应 脉冲激光沉淀 钙钛矿型锰氧化物 稀土 

分 类 号：TQ028.21[化学工程]