不同离子掺杂对层状钙钛矿氧化物La_(1.3)Sr_(1.7)Mn_2O_7的影响

The Influence of Different Ion Doping on Layered Perovskite La_(1.3)Sr_(1.7)Mn_2O_7

采用固相法制备了La_(1.3-x)R_xSr_(1.7)Mn_2O_7(R=Eu,Gd,Dy;x=0,0.1)系列样品,研究Ln位离子及离子半径对钙钛矿氧化物物性的影响.结果表明:由于Eu、Gd、Dy的半径依次减小,所以La_(1.2)Eu_(0.1)Sr_(1.7)Mn_2O_7、La_(1.2)Gd_(0.1)Sr_(1.7)Mn_2O_7和La_(1.2)Dy_(0.1)Sr_(1.7)Mn_2O_7的晶格失配度依次增大,导致3个样品的磁性、磁转变温度、MI转变温度依次减小乃至消失,电阻率随之增加.其结果归结于畸变引起强的电-声相互作用,导致双交换作用减弱,使样品的物性发生改变.

In this study,La_（1.3-x）R_xSr_（1.7）Mn_2O_7（R=Eu,Gd,Dy;x=0,0.1） series of samples were prepared by solid-phase method to study the effect of Ln ion and ion radius on the properties of perovskite oxide. The results show that the radius of Eu,Gd and Dy increases in order,which leads to the increase the lattice mismatch of La_（1.2）Eu_（0.1）Sr_（1.7）Mn_2O_7、La_（1.2）Gd_（0.1）Sr_（1.7）Mn_2O_7 The magnetic, magnetic transition temperature and MI transition temperature of the three samples decrease and even disappear,and the resistivity increases. The result is due to the strong electro-acoustic interaction caused by the distortion, resulting in the weakening of the double exchange effect, so that the physical properties of the sample change.