摘要
利用标准的固相反应法制备了La(1-x)2/3Ca1/3MnO3(x<0.1)系列具有稀土La空位的庞磁电阻锰氧化物多晶样品。X射线粉末衍射(XRD)测量分析表明所有的样品均为单相,单胞具有正交对称性(Pnma)。分析了不同浓度的La空位对磁电输运性质的影响:随着空位浓度的增大,绝缘体-金属的转变温度(TMI)几乎不变(约为267K),这表明少量的稀土空位不会破坏双交换作用;但当La空位浓度x>0.04时,零场电阻率增大,但磁电阻(MR)值减小;在x=0.04时MR值在转变温度TMI处达到最大值约为220%(8T)。
Samples of manganese oxides La(1-x)2/3Ca(1/3)MnO3(x 〈 0.10) with La-vacancy were prepared by standard solid-state reaction method. All the samples are single phase, with orthorhombic symmetry (Pnma ), analyzed by XRD and with Rietveld Refinement. The effect of different La-site vacancies concentration on electronic transport of La(1-x)2/3Ca(1/3)MnO3 was investigated. The insulator-metal transition temperature (about 267 K) nearly remains unchanged with the increase of vacancy concentration, which indicates that small La-vacancy does not destroy the double exchange interaction. But the electronic resistance increases and MR value decreases with La-vacancy content x 〉 0.04. The maximum of the MR value (8 T) is about 220% at transition temperature( TMI )
出处
《中国稀土学报》
CAS
CSCD
北大核心
2006年第2期201-204,共4页
Journal of the Chinese Society of Rare Earths
基金
国家自然科学基金资助(10474031
90201039)
高等学校博士学科点专项科研基金资助(20020284029)项目