【摘要】 采用空气中固相反应烧结法制备了一系列钙钛矿结构的(La1-xREx)2/3Sr1/3MnO3(RE=Y,Sm,Eu,Tb;x=0.1～0.5)稀土锰氧化物多晶样品。X射线衍射(XRD)分析表明掺杂RE部分替代La以后,样品的晶体结构为正交结构,空间群为Pbnm。在室温(300K)和液氮温度(77K)下分别测试了样品的磁性质,发现磁性质的改变与RE的掺入量以及RE的离子半径有关。在掺Tb的样品中明显存在巨磁电阻效应,磁场为2T,温度为300和77K分别测得(La0.6Tb0.4)2/3Sr1/3MnO3和(La0.7Tb0.3)2/3Sr1/3MnO3的磁电阻(MR)为80%和85%。随着Tb掺杂量的增加,在不同的磁场下,样品电阻 温度关系曲线的峰均向高温方向移动。更多还原

【Abstract】 A series of RE manganite perovskite polycrystal samples of (La_1-xRE_x)_2/3Sr_1/3MnO₃ （RE=Y, Sm, Eu, Tb; x=0.1, 0.2, 0.3, 0.4, 0.5） were prepared by solid state reaction in the air. The XRD analysis of these samples indicate that crystal structure of the samples is orthorhombic (P_bnm). Magnetic properties of these samples were measured at 300 and 77 K separately. The measuring results show that magnetic properties are relative to x and radius of RE ions. The colossal magnetoresistance （CMR） effect at 2 T were observed at 300 K in (La_0.6Tb_0.4)_2/3Sr_1/3MnO₃ and 77 K in (La_0.7Tb_0.3)_2/3Sr_1/3MnO₃, and value of MR is 80% and 85%, separately. For (La_1-xTb_x)_2/3Sr_1/3MnO₃, as x increasing, the peaks of R-T curves shift from lower temperature to higher temperature.更多还原