Co掺杂对铁磁金属La_(0.8)Sr_(0.2)MnO_3磁电阻影响机理  

Mechanism of magnetoresistance impacted by Co doped in La_(0.8)Sr_(0.2)MnO_3 ferromagnetic metallic

作　　者：江阔[1] 

机构地区：[1]西南科技大学国防科技学院,绵阳621010

出　　处：《物理学报》2010年第4期2801-2807,共7页Acta Physica Sinica

摘　　要：通过对La0.8Sr0.2Mn1-yCoyO3(y≤0.2)饱和磁矩和输运的测量,研究了Co对La0.8Sr0.2MnO3的磁电阻影响机制.结果表明,在La0.8Sr0.2Mn1-yCoyO3(y≤0.2)中Co3+离子是低自旋态.由于Mn3+—O—Co3+—O—Mn3+类型的磁交换与Mn3+-Mn4+离子间双交换作用相比较弱,Curie温度TC附近的磁电阻随着Co掺杂量的增加而降低.与此相反,由于Co2+离子与eg巡游电子的反铁磁交换耦合作用,低温区间的磁电阻随着Co掺杂量的增加而升高.Through measurement of saturation magnetic moment and transport of La0.8 Sr0.2 Mn1-y CoyO3（y≤0.2）,the mechanism of magnetoresistance（MR） impacted by Co doping is investigated.The results show that Co3＋ is in the low-spin state in La0.8Sr0.2 Mn1-y CoyO3（y≤0.2）.The magnetic exchange interactions of the type Mn3＋—O—Co3＋—O—Mn3＋ is weaker than that of the double exchange interaction between Mn3 ＋-Mn4 ＋,and the magnetoresistance near the Curie temperature TC decreases with the increase of Co concentration.On the contrary,low-temperature magnetoresistance increases with the increase of Co concentration owing to the antiferromagnetic exchange coupling between Co2＋ and eg itinerant electron.

关 键 词：低自旋 磁电阻 磁交换作用 

分 类 号：TG111[金属学及工艺—物理冶金]