非正分钙钛矿化合物(La_(0.8)Sr_(0.2))_(0.7)MnO_3的磁电阻效应  

Magnetoresistance Effect of Non-stoichiometric (La_(0.8)Sr_(0.2))_(0.7)MnO_3 Perovskite Manganite

作　　者：余江应[1] 刘果红[1] 伍和云[1] 胡秀坤[2] 

机构地区：[1]安徽建筑工业学院数理系,安徽合肥230022 [2]南京大学物理系固体微结构国家重点实验室,江苏南京210093

出　　处：《磁性材料及器件》2006年第2期21-23,27,共4页Journal of Magnetic Materials and Devices

摘　　要：采用固相反应法制备了名义成分为（La0.8Sr0.2）0.7MnO3的多晶钙钛矿锰氧化物，通过电阻率，磁化曲线和居里温度的测量，对其磁性与磁电阻效应进行了研究．样品近似La0.8Sr0.2MnO3／Mn3O4两相复合结构。其电阻率随温度的变化曲线具有双峰特征，特别是其磁电阻比在一个较宽的温区内（220-320K）基本上保持不变，相对正分样品La0.8Sr0.2MnO3而言，非正分样品磁电阻比的温度稳定性大大提高，这一特性也表明了其作为磁电阻传感器材料的可行性．Magnetic properties and magnetoresistance effect of polycrystalline perovskite manganites （La0.8Sr0.2）0.7MnO3 have been investigated by measuring the resistivity, magnetization curves and Curie temperature of samples. The sample exhibits composite structure of magnetic perovsidte phase and Mn3O4 phase. The resistivity vs temperature ρ （T） curves presents a duo-peak behavior. The temperature stability of the magnetoresistance ratio of the （La0.8Sr0.2）0.7MnO3 sample, compared to that of stoichiometric La0.8Sr0.2MnO3, has been improved remarkably. The magnetoresistance ratio almost keeps unchanged in a relatively wide temperature range from 220 K to 320 K, which is feasible for magnetoresistive sensor application.

关 键 词：钙钛矿锰氧化物 磁电阻 居里温度 

分 类 号：O482.5[理学—固体物理]