作　　者： ; ; ;

机构地区： 天津大学理学院现代材料物理研究所

出　　处： 《信息记录材料》 2006年第2期34-38,共5页

摘　　要： 实验详细研究了Ga掺杂对锰基氧化物La1/2(Pr1/4+3y/4Ca3/4-3y/4)1/2Mn1-yGayO3(Mn3+:Mn4+=5:3,y=0,0.02,0.05,0.08和0.10)的磁性和电输运性质的影响。实验发现,用Ga3+离子替代Mn3+离子会显著地抑制样品的铁磁性和金属导电特性。随着Ga掺杂量从0增加到0.10,样品的居里温度TC、金属-绝缘转变温度TM I和最大磁电阻所对应的温度均向低温方向偏移,然而样品的电阻率以及最大磁电阻却显著地增加。除了在金属-绝缘转变温度TM I附近出现的本征庞磁电阻外,我们在低温区域还发现了显著的磁电阻效应,这种低温磁电阻是由多晶样品中的晶界效应导致的。另外,通过对宏观磁性的分析,我们没有发现Pr3+离子对磁性的贡献。实验结果表明:磁稀释和无序效应在决定样品的磁性和电输运性质方面起到了重要的作用。 This work reports detailed investigations on magnetic and transport properties of Ga-doped manganites La1/2（Pr1/4＋3y/4Ca3/4-3y/4）1/2 Mn1-y GayO3 （Mn^3＋： Mn^4＋ =5： 3, y=0,0. 02,0. 05,0. 08, and0. 10）. Thesubstitution of Ga^3＋ for Mn^3 ＋ ion significantly suppresses the ferromagnetism and metallic conduction. As the doping level y increases from 0 to 0. 10, the Curie temperature To, metal-insulator transition temperature TMI and the maximal magnetoresistanee shift to low temperature, while the resistivity and the maximal magnetoresistance are enhanced remarkably. Besides the intrinsic magnetoresistance around TMI, a relative large magnetoresistanee is also observed at low temperature, which originates from spin dependent transport in grain boundaries, in addition, the results of analyzing of maeromagnetic properties imply the absence of magnetic contribution of Pr^3＋ ion. Our results show that magnetic dilution and disorder effects play an important role in magnetic and electrical transport properties for the Ga-doped samples.

关 键 词： 锰基氧化物 磁电阻 双交换作用

领　　域： [化学工程]