脱氧La_(0.5)Ca_(0.5)MnO_3样品的铁磁-反铁磁转变和电阻率变化  

Ferromagnetic-antiferromagnetic transition and resistivity variation of oxygen-deficient La_(0.5)Ca_(0.5)MnO_3 samples

作　　者：马玉彬[1] 

机构地区：[1]北京大学物理学院,北京100871

出　　处：《物理学报》2009年第7期4976-4979,共4页Acta Physica Sinica

摘　　要：研究了氧空位对La0.5Ca0.5MnO3(LCMO)多晶块材的电输运和磁性质的影响.随着氧空位的增加,样品在高温段的电阻率一直增加,并满足绝热小极化子模型,而低温段的电阻率先下降后上升,并出现明显的dR/dT>0的行为,直至最后变为绝缘的.氧空位的增加抑止了反铁磁相的出现,使得脱氧的LCMO样品不发生反铁磁转变,进一步增加氧空位则会抑制铁磁相.We have investigated the influence of oxygen vacancies on electronic transport and magnetic property of polycrystalline bulk La0.5Ca0.5MnO3（LCMO）. With increasing content of oxygen vacancy, its resistivity at high temperature increases monotonically and follows the adiabatic small-polaron model. The resistivity at low temperature first deereases, then increases, and has the behavior of dR/d T 〉 0 evidently. The resistivity at low temperature becomes insulating at last. Increasing the oxygen vacancies depresses the appearance of antiferromagnetic phase. As a result, antiferromagnetic transition does not occurs in oxygen-deficient LCMO samples. On more increasc of oxygen vacancies, ferromagnetic phase will eventually be suppressed.

关 键 词：Lao CAO MNO 反铁磁相变 铁磁相变 脱氧 

分 类 号：O482.5[理学—固体物理] P55[理学—物理]