纳米结构Zn_xFe_(3-x)O_4-α-Fe_2O_3多晶材料中的巨隧道磁电阻效应  

GIANT TUNNELING MAGNETORESISTANCE IN NANOSTRUCTURED Zn_xFe_(3-x) O_(4-α)-Fe_2O_3 POLYCRYSTALLINE MATERIAL

作　　者：都有为[1] 陈鹏[1] 朱建民[1] 邢定钰[1] 

机构地区：[1]南京大学固体微结构物理国家重点实验室物理系,南京210093

出　　处：《物理学报》2001年第11期2275-2277,共3页Acta Physica Sinica

摘　　要：在具有纳米绝缘层的多晶锌铁氧体体系中 ,当晶界为α Fe2 O3纳米量级 ( 6— 7nm)的绝缘层时 ,则构成 (ZnxFe3-xO4 ) α Fe2 O3非均匀体 ,高分辨电子显微镜已证实了这种微结构 ,该体系在 0 .5T磁场、4 .2K温度下 ,磁电阻效应可达12 80 % ,3 0 0℃下为 15 8% .Giant tunneling magnetoresistance effect (TMR) as large as 1280% at 4.2K and 158% at 300K was observed in Zn 0.41 Fe 2.59 O 4-α-Fe 2O 3 polycrystalline sample. The Zn 0.41 Fe 2.59 O 4 grains are separated by insulating α-Fe 2O 3 thin layer boundaries, The pattern of nanostructure has been verified by TEM and HREM and the thickness of α-Fe 2O 3 boundary is about 6-7nm. The huge TMR is attributed to the high spin-polarization of Zn 0.41 Fe 2.59 O 4 grains and insulating antiferromagnetic α-Fe 2O 3 thin layer. The Zn xFe 3-x O 4 ferrite is a new type half-metallic material with a huge TMR at room temperature is interesting to further study in future.

关 键 词：隧道磁电阻效应 锌铁氧体 纳米结构 ZnxFe3-xO4-α-Fe2O3多晶材料 

分 类 号：TB383[一般工业技术—材料科学与工程] TM277[电气工程—电工理论与新技术]