La_(0.7-x)Dy_xSr_(0.3)MnO_3体系的输运行为研究

Transport Properties in La_(0.7-x)Dy_xSr_(0.3)MnO_3 System

研究了La位Dy掺杂对La0.7-xDyxSr0.3MnO3(x=0.00、0.10、0.15、0.20、0.30、0.40、0.50、0.60、0.70)体系输运行为的影响.实验结果表明:随Dy掺杂的增加, 体系由长程铁磁有序向自旋团簇玻璃态、反铁磁状态转变.高掺杂时的输运性质在其磁背景下发生异常,在x=0.50时,发现了在ABO3结构中很少出现过的在Tc附近发生绝缘体-金属相变之后又发生从金属-绝缘体相变的现象;对x=0.60、0.70,在远离Tc的温区体系表现为绝缘体.

The influence of Dy doping at La-site on transport properties of La(0.7-x)DyxSr(0.3)MnO(3) (x=0.00, 0.10, 0.15, 0.20, 0.30, 0.40, 0.50, 0.60, and 0.70) was studied. The experimental results indicate that with increasing Dy doping, the system undergoes a transition from long range ferromagnetic order to the cluster-spin glass state and further to antiferromagnetic order. The transport properties exhibit abnormal behaviour at high doping condition. For x=0.50, a transition from metal to insulator occurs after the occurrence of insulator-metal transition near T,, which seldom occurs in ABO(3) structure. The samples of x=0.60 and 0.70, exhibit insulator behavior far above T-c.