La_(0.7)Ca_(0.3)MnO_3薄膜庞磁电阻(CMR)现象的分析  

Analyses of CMR in La_(0.7)Ca_(0.3)MnO_3 Film

作　　者：任世伟[1] 王爱坤[2] 孙敬伟[1] 赵慈[3] 李志清[3] 白海力[3] 

机构地区：[1]河北科技大学理学院物理系,河北石家庄050018 [2]河北工业大学物理系,天津300130 [3]天津大学物理系,天津300072

出　　处：《中国稀土学报》2003年第4期391-394,共4页Journal of the Chinese Society of Rare Earths

基　　金：国家自然科学基金(10074013);河北省教育厅基金资助项目(2003106)

摘　　要：针对La0.7Ca0.3MnO3薄膜材料中磁团簇的特性及其对材料庞磁电阻(CMR)现象的影响进行了研究。根据实验数据,利用Wagner等提出的数学模型,对La0.7Ca0.3MnO3薄膜中的磁团簇随温度的变化行为特性进行了研究;通过对La0.7Ca0.3MnO3薄膜相关实验数据的拟合,发现La0.7Ca0.3MnO3薄膜的居里温度范围应当在245～250K之间,从而进一步缩小了该材料居里温度的误差范围;还通过计算MR随磁团簇总角量子数J的变化,研究了制约和影响MR值的主要因素,发现磁团簇尺寸在La0.7Ca0.3MnO3薄膜的CMR现象中扮演了重要角色。The properties of the magnetic clusters and its influences on the colossal negat ive magnetoresistance (CMR) in La0.7Ca0.3MnO3 film were studied. According to the experimental data, the variations of the magnetic clusters with temperature were analyzed by using the mathematic model presented by Wagner. On the other hand, the fitting of the experimental data of La0.7Ca 0.3MnO3 film was made and the error band was reduced. It is found that t he value of the Curie temperature is between 245～250 K. In addition, through the calculation of MR dependence of the total azimuthal quantum number, the main factors which confine and influence the values of MR were studied. The results show that the size of the magnetic clusters plays an important role in the CMR p henomena of La0.7Ca0.3MnO3 film.

关 键 词：凝聚态物理 磁性材料 庞磁电阻 Wagner模型 磁团簇 稀土 

分 类 号：O641.122[理学—物理化学]